Updated on 2023/02/05

写真a

 
ONO Yoshiaki
 
Organization
Academic Assembly Institute of Science and Technology Fundamental Sciences Professor
Graduate School of Science and Technology Fundamental Sciences Professor
Faculty of Science Department of Science Professor
Title
Professor
External link

Degree

  • 理学博士 ( 1991.3   名古屋大学 )

Research Interests

  • High-temperture superconductivity

  • Strongly correlated electron systems

  • Heavy-fermion systems

  • Theoretical solid state physics

  • First-principles calculations

Research Areas

  • Natural Science / Mathematical physics and fundamental theory of condensed matter physics

  • Natural Science / Magnetism, superconductivity and strongly correlated systems

Research History (researchmap)

  • Niigata University   Faculty of Science Department of Science   Professor

    2017.4

      More details

  • Niigata University   Graduate School of Science and Technology Fundamental Sciences   Professor

    2010.4

      More details

  • Niigata University   Graduate School of Science and Technology Fundamental Sciences   Professor

    2010.4

      More details

  • Niigata University   Faculty of Science Department of Physics   Professor

    2003.9 - 2017.3

      More details

  • 名古屋大学理学研究科   助教授

    1996.6 - 2003.8

      More details

  • 名古屋大学理学研究科   助手

    1996.4 - 1996.5

      More details

  • Nagoya University   School of Science   Research Assistant

    1992.4 - 1996.3

      More details

  • Nagoya University   School of Science   Special researcher of the Japan Society for the Promotion of Science

    1991.4 - 1992.3

      More details

▶ display all

Research History

  • Niigata University   Faculty of Science Department of Science   Professor

    2017.4

  • Niigata University   Graduate School of Science and Technology Fundamental Sciences   Professor

    2010.4

  • Niigata University   Graduate School of Science and Technology Fundamental Sciences   Professor

    2010.4

  • Niigata University   Faculty of Science Department of Physics   Professor

    2003.9 - 2017.3

Education

  • Nagoya University   Graduate School, Division of Natural Science

    - 1991.3

      More details

    Country: Japan

    researchmap

  • Kanazawa University   Faculty of Science

    - 1986.3

      More details

    Country: Japan

    researchmap

 

Papers

  • Electronic States of Al–Mg–Zn Quasicrystal and Its Approximant Based on First‐Principles Calculations Reviewed

    Masaki Saito, Takuya Sekikawa, Yoshiaki Ōno

    physica status solidi (b)   2000108 - 2000108   2020.6

     More details

    Publishing type:Research paper (scientific journal)   Publisher:Wiley  

    DOI: 10.1002/pssb.202000108

    researchmap

    Other Link: https://onlinelibrary.wiley.com/doi/full-xml/10.1002/pssb.202000108

  • First-Principles Study and Orbital-Fluctuation Effect on the Superconductivity in Tungsten Bronze AxWO3 Reviewed

    Takuya Sekikawa, Rai Watabe, Jun Ishizuka, Yoshihiro Nitta, Kazuhiro Sano, Yoshiaki Ōno

    Proceedings of the International Conference on Strongly Correlated Electron Systems (SCES2019)   2020.3

     More details

    Publishing type:Research paper (international conference proceedings)   Publisher:Journal of the Physical Society of Japan  

    DOI: 10.7566/jpscp.30.011043

    researchmap

  • RKKY Interaction and Quadrupole Order in PrT2Al20 (T = Ti, V) Based on Effective 196 Orbital Model Extracted from First-Principles Calculation Reviewed

    Yuto Iizuka, Takemi Yamada, Katsurou Hanzawa, Yoshiaki Ōno

    Proceedings of the International Conference on Strongly Correlated Electron Systems (SCES2019)   2020.3

     More details

    Publishing type:Research paper (international conference proceedings)   Publisher:Journal of the Physical Society of Japan  

    DOI: 10.7566/jpscp.30.011152

    researchmap

  • Dynamical Mean-Field Study of Excitonic Phase in the Spinless Two-Band Hubbard Model for Electron–Hole System Reviewed

    Kento Sasaki, Takemi Yamada, Kaoru Domon, Yoshiaki Ōno

    Proceedings of the International Conference on Strongly Correlated Electron Systems (SCES2019)   2020.3

     More details

    Publishing type:Research paper (international conference proceedings)   Publisher:Journal of the Physical Society of Japan  

    DOI: 10.7566/jpscp.30.011070

    researchmap

  • FFLO Superconductivity Mediated by Excitonic Fluctuation in Semimetallic Ta2NiSe5 Reviewed

    Takemi Yamada, Kaoru Domon, Yoshiaki Ōno

    Journal of the Physical Society of Japan   88 ( 6 )   064701 - 064701   2019.6

     More details

    Publishing type:Research paper (scientific journal)   Publisher:Physical Society of Japan  

    DOI: 10.7566/jpsj.88.064701

    researchmap

  • Fermi surface, pressure-induced antiferromagnetic order, and superconductivity in FeSe Reviewed

    Jun Ishizuka, Takemi Yamada, Yuki Yanagi, Yoshiaki Ono

    Journal of the Physical Society of Japan   87 ( 1 )   014705-1 - 014705-9   2018

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:Physical Society of Japan  

    The pressure dependence of the structural (Ts), antiferromagnetic (Tm), and superconducting (Tc) transition temperatures in FeSe is investigated on the basis of the 16-band d-p model. At ambient pressure, a shallow hole pocket disappears due to the correlation effect, as observed in the angular-resolved photoemission spectroscopy (ARPES) and quantum oscillation (QO) experiments, resulting in the suppression of the antiferromagnetic order, in contrast to the other iron pnictides. The orbital-polarization interaction between the Fe d orbital and Se p orbital is found to drive the ferro-orbital order responsible for the structural transition without accompanying the antiferromagnetic order. The pressure dependence of the Fermi surfaces is derived from the first-principles calculation and is found to well account for the opposite pressure dependences of Ts and Tm, around which the enhanced orbital and magnetic fluctuations cause the double-dome structure of the eigenvalue λ in the Eliashberg equation, as consistent with that of Tc in FeSe.

    DOI: 10.7566/JPSJ.87.014705

    Scopus

    researchmap

  • Excitonic phase diagram of the three-chain hubbard model for semiconducting and semimetallic Ta2NiSe5 Reviewed

    Kaoru Domon, Takemi Yamada, Yoshiaki Ōno

    Journal of the Physical Society of Japan   87 ( 5 )   054701-1 - 054701-8   2018

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:Physical Society of Japan  

    Transition metal chalcogenide Ta2NiSe5, a promising material for the excitonic insulator, is investigated on the basis of the three-chain Hubbard model with two conduction (c) bands and one valence (f) band. In the semimetallic case where only one of two c bands and the f band cross the Fermi level, the transition from the c–f compensated semimetal to the uniform excitonic order, the so-called excitonic insulator, takes place at low temperature as the same as in the semiconducting case. On the other hand, when another c band also crosses the Fermi level, the system shows three types of Fulde–Ferrell–Larkin–Ovchinnikov (FFLO) excitonic orders characterized by the condensation of excitons with finite center-of-mass momentum q corresponding to the three types of nesting vectors between the imbalanced two c and one f Fermi surfaces. The obtained FFLO excitonic states are metallic in contrast to the excitonic insulator and are expected to be observed in the semimetallic Ta2NiSe5 under high pressure. The effect of the electron–lattice coupling is also discussed briefly and is found to induce the monoclinic distortion not only in the uniform excitonic state but also in the FFLO one resulting in the orthorhombic-monoclinic structural phase transition for both cases as observed in Ta2NiSe5 for both low-pressure semiconducting and high-pressure semimetallic regimes.

    DOI: 10.7566/JPSJ.87.054701

    Scopus

    researchmap

  • Anomalous Oscillations due to Aharonov-Bohm and Aharonov-Casher Effects of the One-Dimensional Hubbard Ring in the Strong Coupling Limit Reviewed

    Kazuhiro Sano, Yoshiaki Ono

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   85 ( 12 )   124716-1 - 124716-6   2016.12

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:PHYSICAL SOC JAPAN  

    We investigate anomalous oscillations due to the Aharonov-Bohm (AB) and Aharonov-Casher (AC) effects of the one-dimensional Hubbard ring with flux in the strong coupling limit. By using the exact diagonalization method and the Shiba transformation, we examine the energies of the ground-state and a few excited states in the presence of the flux producing the AB or AC effect, where the transformation not only reverses the sign of the interaction U but also exchanges the role between the AB and AC effects in the model Hamiltonian. We systematically classify the AB and AC oscillations by using the number of minima N-min of the ground-state energy as a function of a normalized phase shift phi for 0 <= phi < 1, and clarify the close relationship between the AB and AC effects. For example, it is shown that N-min is given by N-L - N-e (N-L - N-up arrow + N-down arrow) for the AB (AC) effect in the very strong attraction, where N-L, Ne, N-up arrow, and N-down arrow are the system size, the total number of electrons, the number of electrons with up-spin, and the number of electrons with down-spin, respectively, under the condition of NL > Ne > N-up arrow > N-down arrow. In more special cases, such as for a half-filled band and the spin-balanced case (NL = Ne and N-up arrow = N-down arrow), we find Nmin to be 0 (2) for the AB (AC) effect in the case of very strong repulsion. These results show us the nature of interesting phenomena originating from the interplay between the strong correlation and the quantum interference effect in a mesoscopic ring.

    DOI: 10.7566/JPSJ.85.124716

    Web of Science

    researchmap

  • Effect of Pressure on Magneto-Transport Properties in the Superconducting and Normal Phases of the Metallic Double Chain Compound Pr2Ba4Cu7O15-delta Reviewed

    Masayoshi Kuwabara, Michiaki Matsukawa, Keisuke Sugawara, Haruka Taniguchi, Akiyuki Matsushita, Makoto Hagiwara, Kazuhiro Sano, Yoshiaki Ono, Takahiko Sasaki

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   85 ( 12 )   124704-1 - 124704-6   2016.12

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:PHYSICAL SOC JAPAN  

    To examine the electronic phase diagram of superconducting CuO double chains, we report the effect of external pressure on the magneto-transport properties in superconducting and non-superconducting polycrystalline samples of Pr2Ba4Cu7O15-delta at low temperatures (1.8-40 K) under various magnetic fields (up to 14 T). In the as-sintered non-superconducting sample, the magneto-resistance (MR) follows a power law of H-3/2 at low temperatures, which is in no agreement with the H-2 dependence of MR in the PrBa2Cu4O8 system. The negative pressure dependence of the superconducting phase is qualitatively consistent with a theoretical prediction on the basis of the Tomonaga-Luttinger liquid theory. The 48-h-reduced superconducting sample at ambient pressure exhibits no clear increase in MR for T > T-c,(on) = 26.5 K. In contrast, with the application of pressure to the superconducting sample, the MR effects reappear and are also well fitted by H-3/2. The model of slightly warped Fermi surfaces explains not only the MR effect of the non-superconducting sample, but is also related to the reasons for the pressure-induced MR phenomena of the superconducting sample.

    DOI: 10.7566/JPSJ.85.124704

    Web of Science

    researchmap

  • Hole-s(+/-) State Induced by Coexisting Ferro- and Antiferromagnetic and Antiferro-orbital Fluctuations in Iron Pnictides Reviewed

    Jun Ishizuka, Takemi Yamada, Yuki Yanagi, Yoshiaki Ono

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   85 ( 11 )   114709-1 - 114709-8   2016.11

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:PHYSICAL SOC JAPAN  

    The five-orbital Hubbard model for iron- based superconductors is investigated using the dynamical mean-field theory combined with the Eliashberg equation to clarify the local correlation effects on the electronic states and the superconductivity. In the specific case where the antiferromagnetic (AFM) and antiferro-orbital (AFO) fluctuations are comparably enhanced, the orbital dependence of the vertex function is significantly large, while that of the self-energy is small, in contrast to the AFM fluctuation-dominated case where the vertex function (the self-energy) shows a small (large) orbital dependence. The orbital-dependent vertex function together with the nesting between the inner and outer hole Fermi surfaces results in the enhancement of the inter-orbital ferromagnetic (FM) fluctuation in addition to the AFM and AFO fluctuations. In this case, the hole-s(+/-)-wave pairing with the sign change of the two hole Fermi surfaces is mediated by the coexisting three fluctuations as expected to be observed in the specific compound LiFeAs.

    DOI: 10.7566/JPSJ.85.114709

    Web of Science

    researchmap

  • First- and Second-Order Phase Transitions between the Uniform and FFLO Excitonic States in the Three-Chain Hubbard Model for Ta2NiSe5 Reviewed

    Kaoru Domon, Takemi Yamada, Yoshiaki Ono

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   85 ( 6 )   065005-1 - 065005-2   2016.6

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:PHYSICAL SOC JAPAN  

    We examine the free energy and the thermodynamic properties in the three-chain Hubbard model for Ta2NiSe5 to clarify the phase transitions between the uniform and the FFLO excitonic states which are expected to be observed in Ta2NiSe5 under high pressure.

    DOI: 10.7566/JPSJ.85.065005

    Web of Science

    researchmap

  • FFLO Excitonic State in the Three-Chain Hubbard Model for Ta2NiSe5 Reviewed

    Takemi Yamada, Kaoru Domon, Yoshiaki Ono

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   85 ( 5 )   053703-1 - 053703-5   2016.5

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:PHYSICAL SOC JAPAN  

    The three-chain Hubbard model for Ta2NiSe5, known as a candidate material for an excitonic insulator, is investigated over the wide range of the energy gap D between the twofold degenerate conduction bands and the nondegenerate valence band including both semiconducting (D > 0) and semimetallic (D < 0) cases. In the semimetallic case, the difference in the band degeneracy inevitably causes the imbalance of each Fermi wavenumber, resulting in a remarkable excitonic state characterized by the condensation of excitons with finite center-of-mass momentum q, the so-called Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) excitonic state. With decreasing D corresponding to increasing pressure, the obtained excitonic phase diagram shows a crossover from BEC (D greater than or similar to 0) to BCS (D less than or similar to 0) regime, and then shows a distinct phase transition at a certain critical value D-c (< 0) from the uniform (q = 0) to the FFLO (q not equal 0) excitonic state, as expected to be observed in Ta2NiSe5 under high pressure.

    DOI: 10.7566/JPSJ.85.053703

    Web of Science

    researchmap

  • Theoretical analysis of pressure dependence on the electronic states of FeSe

    Ishizuka Jun, Yamada Takemi, Yanagi Yuki, Ono Yoshiaki

    Meeting Abstracts of the Physical Society of Japan   71   1833 - 1833   2016

     More details

    Language:Japanese   Publisher:The Physical Society of Japan  

    DOI: 10.11316/jpsgaiyo.71.2.0_1833

    CiNii Article

    researchmap

  • Anomalous properties in the FFLO excitonic phase on the 3-chain Hubbard model for Ta2NiSe5

    Domon Kaoru, Yamada Takemi, Ono Yoshiaki

    Meeting Abstracts of the Physical Society of Japan   71   1828 - 1828   2016

     More details

    Language:Japanese   Publisher:The Physical Society of Japan  

    DOI: 10.11316/jpsgaiyo.71.2.0_1828

    CiNii Article

    researchmap

  • Excitonic state and superconductivity due to the excitonic fluctuation on the 3-chain Hubbard model for Ta2NiSe5 II

    Yamada Takemi, Domon Kaoru, Ono Yoshiaki

    Meeting Abstracts of the Physical Society of Japan   71   1827 - 1827   2016

     More details

    Language:Japanese   Publisher:The Physical Society of Japan  

    DOI: 10.11316/jpsgaiyo.71.2.0_1827

    CiNii Article

    researchmap

  • 21aPS-15 FFLO excitonic state on the 3-chain Hubbard model for Ta_2NiSe_5

    Domon Kaoru, Yamada Takemi, Ono Yoshiaki

    Meeting Abstracts of the Physical Society of Japan   71   2212 - 2212   2016

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    DOI: 10.11316/jpsgaiyo.71.1.0_2212

    CiNii Article

    CiNii Books

    researchmap

  • Novel s-wave due to coexisting ferro- and antiferromagnetic fluctuations in iron pnictides Reviewed

    Jun Ishizuka, Takemi Yamada, Yoshiaki Ono

    INTERNATIONAL CONFERENCE ON STRONGLY CORRELATED ELECTRON SYSTEMS 2014 (SCES2014)   592 ( 1 )   012077-1 - 012077-5   2015

     More details

    Language:English   Publishing type:Research paper (international conference proceedings)   Publisher:IOP PUBLISHING LTD  

    The five-orbital Hubbard model for iron pnictides is investigated by using the dynamical mean-field theory (DMFT) in conjunction with the Eliashberg equation in the strong correlation regime where the ferromagnetic (FM) and antiferromagnetic (AFM) fluctuations are simultaneously enhanced. When the intraorbital Coulomb interaction is a little smaller than the interorbital one, the FM fluctuation is largely enhanced due to the significant orbital dependence of the vertex correction and becomes comparable to the AFM fluctuation, in contrast to the result from the random phase approximation where the AFM fluctuation is exclusively enhanced due to the nesting between hole and electron Fermi surfaces (FSs). The enhanced FM fluctuation induces the large repulsive pairing interaction between inner and outer hole FSs while the AFM fluctuation does between the hole and electron FSs. The latter is partially counteracted by the attractive pairing interaction mediated by the antiferro-orbital fluctuation. The resulting pairing state is found to be a novel s-wave in which the gap function of the inner hole FS has the opposite sign to that of the outer hole and electron FSs.

    DOI: 10.1088/1742-6596/592/1/012077

    Web of Science

    researchmap

  • 22aBE-12 A role of orbital fluctuation in A15-type superconductors and comparison with iron-based superconductors

    Yamada Takemi, Ogata Kei, Ono Yoshiaki

    Meeting Abstracts of the Physical Society of Japan   70   2098 - 2098   2015

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    DOI: 10.11316/jpsgaiyo.70.1.0_2098

    CiNii Article

    CiNii Books

    researchmap

  • 24aPS-42 Spin and charge-orbital fuctuations and superconductivity in the multi-orbital d-p model for high-T_c cuprates

    Hoshi T., Ishizuka J., Yamada T., Ono Y.

    Meeting Abstracts of the Physical Society of Japan   70   2394 - 2394   2015

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    DOI: 10.11316/jpsgaiyo.70.1.0_2394

    CiNii Article

    CiNii Books

    researchmap

  • 24aPS-46 DMFT+Eliashberg Study for Iron-based Superconductors

    Ishizuka J., Yamada T., Yanagi Y., Ono Y.

    Meeting Abstracts of the Physical Society of Japan   70   2398 - 2398   2015

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    DOI: 10.11316/jpsgaiyo.70.1.0_2398

    CiNii Article

    CiNii Books

    researchmap

  • 24aPS-27 The effect of AB intersite d-p orbital correlation in A15 compound (A_3B)

    Ogata K., Yamada T., Ishizuka J., Ono Y.

    Meeting Abstracts of the Physical Society of Japan   70   2380 - 2380   2015

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    DOI: 10.11316/jpsgaiyo.70.1.0_2380

    CiNii Article

    CiNii Books

    researchmap

  • 18pDB-6 Structural transition and superconductivity in multi-band systems due to cooperation of intersite Coulomb interaction and electron phonon coupling

    Yamada Takemi, Ono Yoshiaki

    Meeting Abstracts of the Physical Society of Japan   70   2042 - 2042   2015

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    DOI: 10.11316/jpsgaiyo.70.2.0_2042

    CiNii Article

    CiNii Books

    researchmap

  • 18pDB-2 Electronic state and superconductivity in multi-orbital d-p model by using the dynamical mean-field theory

    Ishizuka J., Yamada T., Yanagi Y., Ono Y.

    Meeting Abstracts of the Physical Society of Japan   70   2038 - 2038   2015

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    DOI: 10.11316/jpsgaiyo.70.2.0_2038

    CiNii Article

    CiNii Books

    researchmap

  • Metal-Insulator Transition and Superconductivity in the Two-Orbital Hubbard-Holstein Model for Iron-Based Superconductors Reviewed

    Takemi Yamada, Jun Ishizuka, Yoshiaki Ono

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   83 ( 4 )   044711-1 - 044711-8   2014.4

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:PHYSICAL SOC JAPAN  

    We investigate a two-orbital model for iron-based superconductors to elucidate the effect of interplay between electron correlation and Jahn-Teller electron-phonon coupling by using the dynamical mean-field theory combined with the exact diagonalization method. When the intra-and inter-orbital Coulomb interactions, U and U', increase with U = U', both the local spin and orbital susceptibilities, chi(s) and chi(o), increase with chi(s) = chi(o) in the absence of the Hund's rule coupling J and the electron-phonon coupling g. In the presence of J and g, there are distinct two regimes: for J greater than or similar to 2g(2)/omega(0) with the phonon frequency omega(0), chi s is enhanced relative to chi(o) and shows a divergence at J = J(c) above which the system becomes Mott insulator, while for J less than or similar to 2g(2)/omega(0), chi(o) is enhanced relative to chi(s) and shows a divergence at g = g(c) above which the system becomes bipolaronic insulator. In the former regime, the superconductivity is mediated by antiferromagnetic fluctuations enhanced due to Fermi-surface nesting and is found to be largely dependent on carrier doping. On the other hand, in the latter regime, the superconductivity is mediated by ferro-orbital fluctuations and is observed for wide doping region including heavily doped case without the Fermi-surface nesting.

    DOI: 10.7566/JPSJ.83.044711

    Web of Science

    researchmap

  • A High-T-c Mechanism of Iron Pnictide Superconductivity due to Cooperation of Ferro-Orbital and Antiferromagnetic Fluctuations Reviewed

    Takemi Yamada, Jun Ishizuka, Yoshiaki Ono

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   83 ( 4 )   043704-1 - 043704-4   2014.4

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:PHYSICAL SOC JAPAN  

    The electronic states and superconductivity in iron pnictides are studied on the basis of the 16 band d-p model which includes both the onsite Coulomb interaction between Fe d electrons and the intersite one between Fe d and pnictogen p electrons. The model well accounts for experimentally observed two fluctuations: the d-d interaction-enhanced antiferromagnetic (AFM) fluctuation and the d-p interaction-enhanced ferro-orbital (FO) fluctuation responsible for the C-66 elastic softening. The AFM fluctuation induces the repulsive pairing interaction for q similar to Q(AF) while the FO does the attractive one for q similar to 0 resulting in the s(+/-)-wave superconductivity where the two fluctuations cooperatively enhance the superconducting transition temperature T-c without any competition by virtue of the q-space segregation.

    DOI: 10.7566/JPSJ.83.043704

    Web of Science

    researchmap

  • FFLO state and anomalous flux quantization in the one-dimensional attractive Hubbard models with imbalanced spin populations Reviewed

    Kazuhiro Sano, Yoshiaki Ono

    JPS Conference Proceedings   3   015041-1 - 015041-6   2014

     More details

    Language:English   Publishing type:Research paper (international conference proceedings)   Publisher:The Physical Society of Japan  

    DOI: 10.7566/JPSCP.3.015041

    CiNii Article

    researchmap

  • Dynamical Mean-Field Study on the Superconductivity Mediated by Spin and Orbital Fluctuations in the Five-Orbital Hubbard Model for Iron Pnictides Reviewed

    Jun Ishizuka, Takemi Yamada, Yuki Yanagi, Yoshiaki Ono

    JPS Conference Proceedings   3   015020-1 - 015020-5   2014

     More details

    Language:English   Publishing type:Research paper (international conference proceedings)   Publisher:The Physical Society of Japan  

    DOI: 10.7566/JPSCP.3.015020

    CiNii Article

    researchmap

  • Local Correlation Effects on the s(+/-)- and s(++)- Wave Superconductivities Mediated by Magnetic and Orbital Fluctuations in the Five-Orbital Hubbard Model for Iron Pnictides Reviewed

    Jun Ishizuka, Takemi Yamada, Yuki Yanagi, Yoshiaki Ono

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   82 ( 12 )   123712-1 - 123712-5   2013.12

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:PHYSICAL SOC JAPAN  

    We investigate the electronic state and the superconductivity in the five-orbital Hubbard model for iron pnictides by using the dynamical mean-field theory in conjunction with the Eliashberg equation. The renormalization factor exhibits significant orbital dependence resulting in the large change in the band dispersion as observed in recent ARPES experiments. The critical interactions towards the magnetic, orbital and superconducting instabilities are suppressed as compared with those from the random phase approximation (RPA) due to local correlation effects. Remarkably, the s(++)-pairing phase due to the orbital fluctuation is largely expanded relative to the RPA result, while the s(+/-)-pairing phase due to the magnetic fluctuation is reduced.

    DOI: 10.7566/JPSJ.82.123712

    Web of Science

    researchmap

  • Hall coefficient in the superconducting and non-superconducting Pr <inf>2</inf>Ba<inf>4</inf>Cu<inf>7</inf>O<inf>15-δ</inf> compounds with metallic double chains Reviewed

    Junki Tada, Michiaki Matsukawa, Takahisa Konno, Satoru Kobayashi, Makoto Hagiwara, Tsuyoshi Miyazaki, Kazuhiro Sano, Yoshiaki Ono, Akiyuki Matsushita

    Journal of the Physical Society of Japan   82 ( 10 )   105003-1 - 105003-2   2013.10

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:The Physical Society of Japan  

    DOI: 10.7566/JPSJ.82.105003

    Scopus

    researchmap

  • Effect of magnetic field on the superconducting phase in the electron-doped metallic double-chain compound Pr<inf>2</inf>Ba<inf>4</inf>Cu<inf>7</inf>O <inf>15-δ</inf> Reviewed

    Taiji Chiba, Michiaki Matsukawa, Junki Tada, Satoru Kobayashi, Makoto Hagiwara, Tsuyoshi Miyazaki, Kazuhiro Sano, Yoshiaki Öno, Takahiko Sasaki, Jun Ichi Echigoya

    Journal of the Physical Society of Japan   82 ( 7 )   074706-1 - 074706-6   2013.7

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:The Physical Society of Japan  

    We report the magnetotransport and dc magnetic susceptibility of the polycrystalline samples of Pr2Ba4Cu7O 15-δ, to examine the effect of magnetic field on the superconducting phase of the metallic CuO double-chain. The resistive critical magnetic field is estimated to be about 21 T at low temperatures from the resistive transition data. On the other hand, the corresponding critical field determined from the magnetization measurements gives rise to a very low value of ̃0.3 T at 2 K. These discrepancies in the magnetic response between the resistivity and magnetization data are caused by disappearance of the magnetically shielding effect even in relatively lower fields. In spite of the observation of the resistive drop associated with the superconducting transport currents, the suppression of the diamagnetic signal is probably related to the superconductivity of quasi one-dimensional CuO double-chain. The behavior of Seebeck coefficient in the superconducting Pr2Ba4Cu 7O15-δ is discussed on the basis of the double chain model from the density functional band calculation. © 2013 The Physical Society of Japan.

    DOI: 10.7566/JPSJ.82.074706

    Scopus

    researchmap

  • Anomalous Flux Quantization in the Spin-Imbalanced Attractive Hubbard Ring Reviewed

    Kazuhiro Sano, Yoshiaki Ono

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   82 ( 5 )   054707-1 - 054707-5   2013.5

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:PHYSICAL SOC JAPAN  

    We investigate the one-dimensional Hubbard ring with attractive interaction in the presence of imbalanced spin populations by using the exact diagonalization method. The singlet pairing correlation function is found to show spatial oscillations with power-law decay as expected in the Fulde-Ferrell-Larkin-Ovchinnikov state of a Tomonaga-Luttinger liquid. In the strong coupling regime, the system shows an anomalous flux quantization of period h/4e, half of the superconducting flux quantum of h/2e, as recently predicted by mean-field analysis, together with various flux quanta smaller than h/4e. Notably, the observed flux quanta are determined by the difference between the system size N-L and electron number N-e as h/(N-L - N-e)e.

    DOI: 10.7566/JPSJ.82.054707

    Web of Science

    researchmap

  • Structural transition, ferro-orbital order and its fluctuation-mediated s(++)-wave superconductivity in iron pnictides Invited Reviewed

    Yoshiaki Ono, Yuki Yanagi, Naoko Adachi, Youichi Yamakawa

    SOLID STATE COMMUNICATIONS   152 ( 8 )   701 - 710   2012.4

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:PERGAMON-ELSEVIER SCIENCE LTD  

    We investigate the electronic states and the superconductivity in the two-dimensional 16-band d-p model extracted from a tight-binding fit to the band structure of iron pnictides, in the presence of both the Coulomb interaction between Fe d-electrons and the electron-lattice coupling g with the orthorhombic mode which is crucial for reproducing the recently observed ultrasonic softening of the elastic constant C-66. Due to the cooperative effects of these interactions, the ferro-orbital order with different occupations of d(yz) and d(zx) orbitals occurs and induces the tetragonal-orthorhombic structural transition at T-s, together with the stripe-type antiferromagnetic (AFM) order below T-N. For a large g case, we obtain the phase diagram consistent with the doped iron pnictides with T-s &gt; T-N for x &gt; 0, where the s(++)-wave superconductivity is mediated by the ferro-orbital fluctuation which is largely enhanced near the ferro-orbital QCP at x(c) with T-s -&gt; 0. On the other hand, for a small g case, the simultaneous phase transition occurs at T-s = T-N even for x &gt; 0, where the s(+/-)-wave superconductivity is mediated by the AFM fluctuation. Both the s-wave states with full superconducting gaps are consistent with most of the experiments but only the former is considered to account for the small T-c-suppression against nonmagnetic impurities. (C) 2012 Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.ssc.2012.01.017

    Web of Science

    researchmap

  • Dynamical mean-field theory for the anisotropic Kondo semiconductor: Temperature and magnetic field dependence Reviewed

    Takemi Yamada, Yoshiaki Ono

    PHYSICAL REVIEW B   85 ( 16 )   165114-1 - 165114-10   2012.4

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:AMER PHYSICAL SOC  

    We investigate the periodic Anderson model with k-dependent c-f mixing reproducing the point nodes of the hybridization gap by using the dynamical mean-field theory combined with the exact diagonalization method. At low temperature below a coherence temperature T-0, the imaginary part of the self-energy is found to be proportional to T-2 and the pseudogap with two characteristic energies (Delta) over tilde (1) and (Delta) over tilde (2) is clearly observed for T &lt;&lt; T-0, while the pseudogap is smeared with increasing T and then disappears at high temperature T greater than or similar to T-0 due to the evolution of the imaginary self-energy. When the Coulomb interaction between f electrons U increases, (Delta) over tilde (1), (Delta) over tilde (2), and T-0 together with T-max at which the magnetic susceptibility is maximum decrease in proportion to the renormalization factor Z resulting in a heavy-fermion semiconductor with a large mass enhancement m*/m = Z(-1) for large U. We also examine the effect of the external magnetic field H and find that the magnetization M shows two metamagnetic anomalies H-1 and H-2 corresponding to (Delta) over tilde (1) and (Delta) over tilde (2) which are reduced due to the effect of H together with Z. Remarkably, Z(-1) is found to be largely enhanced due to H especially for H-1 less than or similar to H less than or similar to H-2, where the field induced heavy fermion state is realized. The obtained results seem to be consistent with the experimental results observed in the anisotropic Kondo semiconductors such as CeNiSn.

    DOI: 10.1103/PhysRevB.85.165114

    Web of Science

    researchmap

  • Heavy-Electron Formation and Polaron-Bipolaron Transition in the Anharmonic Holstein Model Reviewed

    Takahiro Fuse, Yoshiaki Ono, Takashi Hotta

    Journal of the Physical Society of Japan   81 ( 4 )   044701-1 - 044701-11   2012.3

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:The Physical Society of Japan  

    DOI: 10.11+RC43/JPSJ.81.044701

    researchmap

  • Dynamical Mean-Field Study of Metamagnetism in Heavy Fermion Systems Reviewed

    Takemi Yamada, Yoshiaki Ono

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   80 ( Supplement A )   131-1 - 131-3   2011.7

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:PHYSICAL SOC JAPAN  

    We investigate the metamagnetism in the periodic Anderson model with the k-dependent c - f mixing by using the dynamical mean-field theory combined with the exact diagonalization method. It is found that both effects of the k-dependent c - f mixing and strong correlation due to the Coulomb interaction between f electrons are significant for determining both the magnetization and the mass enhancement factor. For the case away from the half-filling, the results is consistent with the metamagnetic behavior observed in CeRu2Si2

    DOI: 10.1143/JPSJS.80SA.SA131

    Web of Science

    researchmap

  • Heavy Fermions due to Cooperative Effects of Coulomb and Electron-Phonon Interactions in the Two-Orbital Periodic Anderson Model Reviewed

    Keisuke Mitsumoto, Yoshiaki Ono

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   80 ( Supplement A )   138-1 - 138-3   2011.7

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:PHYSICAL SOC JAPAN  

    Using the dynamical mean-field theory, we investigate the two-orbital periodic Anderson model including both the Coulomb interaction U between f-electrons and the electron-phonon interaction g which couple the local orbital fluctuations off-electrons with Jahn-Teller phonons. It is found that the heavy fermion state caused by U is largely enhanced due to the effect of g. In the heavy fermion state for large U and g, both the orbital and lattice fluctuations are enhanced, while the charge (valence) and spin fluctuations are suppressed; this is a nonmagnetic origin of the heavy fermions. The effect of the mass enhancement for the case with twofold-degenerate phonon mode is larger than that for one phonon mode. The obtained results show a possible nonmagnetic origin of the heavy fermion state recently observed in SmOs4Sb12.

    DOI: 10.1143/JPSJS.80SA.SA138

    Web of Science

    researchmap

  • Rattling-Induced Heavy Fermion State in the Anharmonic Holstein Model Reviewed

    Takahiro Fuse, Yoshiaki Ono

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   80 ( Supplement A )   136-1 - 136-3   2011.7

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:PHYSICAL SOC JAPAN  

    We investigate the heavy fermion states in the half-filled anharmonic Holstein model by using the dynamical mean-field theory combined with the exact diagonalization method at low temperatures down to 1/10(4) of the conduction bandwidth. For the weak anharmonic cases with single-well or shallow double-well potentials, the bipolaronic first order phase transition takes place at a critical value of the electron-phonon coupling below a critical temperature as recently observed in the harmonic Holstein model. On the other hand, for the strong anharmonic case with deep double-well potential, the bipolaronic transition is suppressed and changes to a crossover where the heavy fermion state with a large effective mass is realized due to the effect of largely anharmonic local oscillations called rattling.

    DOI: 10.1143/JPSJS.80SA.SA136

    Web of Science

    researchmap

  • Electronic States and Superconducting Transition Temperature Based on the Tomonaga-Luttinger Liquid in Pr2Ba4Cu7O15-delta Reviewed

    Tatsuro Habaguchi, Yoshiaki Ono, Hai Ying Du Gh, Kazuhiro Sano, Yuh Yamada

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   80 ( 2 )   024708-1 - 024708-4   2011.2

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:PHYSICAL SOC JAPAN  

    An NQR experiment revealed superconductivity of Pr2Ba4Cu7O15-delta (Pr247) to be realized on CuO double chain layers and suggests possibility of novel one-dimensional (1D) superconductivity. To clarify the nature of the 1D superconductivity, we calculate the band dispersions of Pr247 by using the generalized gradient approximation (GGA). It indicates that Fermi surface of CuO double chains is well described to the electronic structure of a quasi-1D system. Assuming the zigzag Hubbard chain model to be an effective model of the system, we derive tight binding parameters of the model from a fit to the result of GGA. Based on the Tomonaga-Luttinger liquid theory, we estimate transition temperature (T-c) of the quasi-1D zigzag Hubbard model from the calculated value of the Luttinger liquid parameter K-rho. The result of T-c is consistent with that of experiments in Pr247 and it suggests that the mechanism of the superconductivity is well understood within the concept of the Tomonaga-Luttinger liquid.

    DOI: 10.1143/JPSJ.80.024708

    Web of Science

    researchmap

  • A possible bipolaronic transition in beta-pyrochlore compounds Reviewed

    T. Fuse, Y. Ono

    PHYSICA C-SUPERCONDUCTIVITY AND ITS APPLICATIONS   470   S701 - S702   2010.12

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:ELSEVIER SCIENCE BV  

    We investigate the Hubbard-Holstein model by using the dynamical mean-field theory combined with the exact diagonalization method. Below a critical temperature T(cr), a coexistence of two solutions, small lattice fluctuating solution (polaronic state) and large one (bipolaronic state), is found for the same value of the electron-phonon coupling g in the range g(c1) &lt; g &lt; g(c2) for a fixed value of the Coulomb interaction U. As the result, the system shows a first-order phase transition at T(p)(&lt;T(cr)) from the bipolaronic to the polaronic states as T decreases. The effective potential for oscillating atoms, which is renormalized due to the effect of g, is double-well type for T &gt; T(p), while it is single-well type for T &lt; T(p). The obtained transition for small U case with small T(p) and discontinuities in physical quantities seems to be account for the rattling transition observed in the beta-pyrochlore oxide KOs(2)O(6). (C) 2010 Elsevier B.V. All rights reserved.

    DOI: 10.1016/j.physc.2010.01.022

    Web of Science

    researchmap

  • Phase diagram of the two-dimensional 16-band d-p model for iron-based superconductors Reviewed

    Y. Yanagi, Y. Yamakawa, Y. Ono

    PHYSICA C-SUPERCONDUCTIVITY AND ITS APPLICATIONS   470   S349 - S350   2010.12

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:ELSEVIER SCIENCE BV  

    The electronic state of the Fe(2)As(2) plane in iron-based superconductors is investigated on the basis of the two-dimensional 16-band d-p model. Using the random phase approximation for the on-site Coulomb interaction between Fe d electrons, we obtain the phase diagram including the magnetic ordered states and the superconductivity. It is found that the s(+/-)-wave superconductivity, where the gap functions have different signs between the electron pockets and the hole pockets, is realized near the incommensurate magnetic ordered phase with q similar to (pi, pi). The absolute values of the gap functions on the Fermi surfaces are almost isotropic but largely depend on the energy bands. (C) 2009 Elsevier B.V. All rights reserved.

    DOI: 10.1016/j.physc.2009.10.109

    Web of Science

    researchmap

  • Orbital Order, Structural Transition, and Superconductivity in Iron Pnictides Reviewed

    Yuki Yanagi, Youichi Yamakawa, Naoko Adachi, Yoshiaki Ono

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   79 ( 12 )   123707-1 - 123707-4   2010.12

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:PHYSICAL SOC JAPAN  

    We investigate the 16-band d-p model for iron pnictide superconductors in the presence of the electron-phonon coupling g with the orthorhombic mode which is crucial for reproducing the recently observed ultrasonic softening. Within the RPA, we obtain the ferro-orbital order below T-Q which induces the tetragonal-orthorhombic structural transition at T-s = T-Q, together with the stripe-type antiferro-magnetic order below T-N. Near the phase transitions, the system shows the s(++)-wave superconductivity due to the orbital fluctuation for a large g case with T-Q &gt; T-N, while the s(+/-)-wave due to the magnetic fluctuation for a small g case with T-Q &lt;= T-N. The former case is consistent with the phase diagram of doped iron pnictides with T-s &gt; T-N.

    DOI: 10.1143/JPSJ.79.123707

    Web of Science

    researchmap

  • First Order Bipolaronic Transition at Finite Temperature in the Holstein Model Reviewed

    Takahiro Fuse, Yoshiaki Ono

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   79 ( 9 )   093702-1 - 093702-4   2010.9

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:PHYSICAL SOC JAPAN  

    We investigate the Holstein model by using the dynamical mean-field theory combined with the exact diagonalization method. Below a critical temperature T-cr, a coexistence of the polaronic and the bipolaronic solutions is found for the same value of the electron-phonon coupling g in the range g(c1)(T) &lt; g &lt; g(c2)(T). In the coexistence region, the system shows a first order phase transition from the bipolaronic to the polaronic states as T decreases at T = T-p (&lt; T-cr), where the double occupancy and the lattice fluctuation together with the anharmonicity of the effective ion potential change discontinuously without any symmetry breaking. The obtained bipolaronic transition seems to be consistent with the rattling transition in the beta-pyrochlore oxide KOs2O6.

    DOI: 10.1143/JPSJ.79.093702

    Web of Science

    researchmap

  • Cooperative effects of Coulomb and electron-phonon interactions in the two-dimensional 16-band d-p model for iron-based superconductors Reviewed

    Yuki Yanagi, Youichi Yamakawa, Naoko Adachi, Yoshiaki Ono

    PHYSICAL REVIEW B   82 ( 6 )   064518-1 - 064518-10   2010.8

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:AMER PHYSICAL SOC  

    We study the electronic states and the superconductivity in the two-dimensional 16-band d-p model coupled with A(1g), B-1g, and E-g local phonons and obtain the rich phase diagram including the magnetic-, charge-, and orbital-ordered phases on the parameter plane of the Coulomb and electron-phonon interactions. When the electron-phonon interaction is dominant, the charge fluctuations induce the s(++)-wave superconductivity, while when the Coulomb interaction is dominant, the magnetic fluctuations induce the s(+/-)-wave superconductivity. Remarkably, the orbital fluctuations are enhanced due to the cooperative effects of the Coulomb and electronphonon interactions and induce the s(++)-wave and the nodal s(+/-)-wave superconductivities.

    DOI: 10.1103/PhysRevB.82.064518

    Web of Science

    researchmap

  • Cooperative Effect of Coulomb Interaction and Electron-Phonon Coupling on the Heavy Fermion State in the Two-Orbital Periodic Anderson Model Reviewed

    Keisuke Mitsumoto, Yoshiaki Ono

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   79 ( 5 )   054707-1 - 054707-7   2010.5

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:PHYSICAL SOC JAPAN  

    We investigate the two-orbital periodic Anderson model, where the local orbital fluctuations of f-electrons couple with a two-fold degenerate Jahn-Teller phonon, by using the dynamical mean-field theory. It is found that the heavy fermion state caused by the Coulomb interaction between f-electrons U is largely enhanced due to the electron-phonon coupling g, in contrast to the case with the single-orbital periodic Anderson model where the effects of U and g compete to each other. In the heavy fermion state for large U and g, both the orbital and lattice fluctuations are enhanced, while the charge (valence) and spin fluctuations are suppressed. In the strong coupling regime, a sharp soft phonon mode with a large spectral weight is observed for small U, while a broad soft phonon mode with a small spectral weight is observed for large U. The cooperative effect of U and g for half-filling with two f-electrons per atom n(f) = 2 is more pronounced than that for quarter-filling with n(f) = 1.

    DOI: 10.1143/JPSJ.79.054707

    Web of Science

    researchmap

  • Two types of s-wave pairing due to magnetic and orbital fluctuations in the two-dimensional 16-band d-p model for iron-based superconductors Reviewed

    Yuki Yanagi, Youichi Yamakawa, Yoshiaki Ono

    PHYSICAL REVIEW B   81 ( 5 )   054518-1 - 054518-10   2010.2

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:AMER PHYSICAL SOC  

    We study superconductivity in the two-dimensional 16-band d-p model extracted from a tight-binding fit to the band structure of LaFeAsO, using the random phase approximation. When the intraorbital repulsion U is larger than the interorbital one U&apos;, an extended s-wave (s(+/-)-wave) pairing with sign reversal of order parameter is mediated by antiferromagnetic spin fluctuations, while when U &lt; U&apos; another kind of s-wave (s(++)-wave) pairing without sign reversal is mediated by ferro-orbital fluctuations. The s(++)-wave pairing is enhanced due to the electron-phonon coupling and then can be expanded over the realistic parameter region with U &gt; U&apos;.

    DOI: 10.1103/PhysRevB.81.054518

    Web of Science

    researchmap

  • Effect of the spin-orbit interaction and the electron phonon coupling on the electronic state in a silicon vacancy Reviewed

    Takemi Yamada, Youichi Yamakawa, Yoshiaki Ono

    INTERNATIONAL CONFERENCE ON MAGNETISM (ICM 2009)   200 ( 1 )   012228-1 - 012228-4   2010

     More details

    Language:English   Publishing type:Research paper (international conference proceedings)   Publisher:IOP PUBLISHING LTD  

    The electronic state around a single vacancy in silicon crystal is investigated by using the Green&apos;s function approach. The triply degenerate charge states are found to be widely extended and account for extremely large elastic softening at low temperature as observed in recent ultrasonic experiments. When we include the LS coupling As, on each Si atom, the 6-fold spin-orbital degeneracy for the V(+) state with the valence +1 and spin 1/2 splits into Gamma(7) doublet groundstates and Gamma(8) quartet excited states with a reduced excited energy of O(lambda(Si)/10). We also consider the effect of couplings between electrons and Jahn-Teller phonons in the dangling bonds within the second order perturbation and find that the groundstate becomes Gamma(8) quartet which is responsible for the magnetic-field suppression of the softening in B-doped silicon.

    DOI: 10.1088/1742-6596/200/1/012228

    Web of Science

    researchmap

  • Effects of ferromagnetic fluctuations on the electric and thermal transport properties in NaxCoO2 Reviewed

    Y. Yanagi, Y. Ono

    INTERNATIONAL CONFERENCE ON MAGNETISM (ICM 2009)   200 ( 1 )   012235-1 - 012235-5   2010

     More details

    Language:English   Publishing type:Research paper (international conference proceedings)   Publisher:IOP PUBLISHING LTD  

    We investigate the electronic states and the transport properties of the CoO2 plane in NaxCoO2 on the basis of the two-dimensional triangular lattice 11-band d-p model by using the fluctuation exchange approximation, where we consider the Coulomb interaction between the t(2g) electrons on a Co site. It is found that all of the effective mass of quasiparticles, the resistivity, the thermoelectric power and the uniform spin susceptibility increase with increasing x for x &gt; 0.6. This implies that the ferromagnetic fluctuations play significant roles on determining the electronic states. These results are qualitatively consistent with the experiments

    DOI: 10.1088/1742-6596/200/1/012235

    Web of Science

    researchmap

  • Antiferromagnetic, Charge and Orbital Order in Na0.5CoO2 Based on the Two Dimensional 11 Bands d-p Model Reviewed

    Youichi Yamakawa, Naohiro Watanabe, Yoshiaki Ono

    INTERNATIONAL CONFERENCE ON MAGNETISM (ICM 2009)   200 ( 1 )   012233-1 - 012233-4   2010

     More details

    Language:English   Publishing type:Research paper (international conference proceedings)   Publisher:IOP PUBLISHING LTD  

    The electronic state of the CoO2 plane in the layered cobalt oxide Na0.5CoO2 is investigated on the basis of the 11 band d-p model on a two dimensional triangular lattice, where the tight-binding parameters are determined so as to fit the LDA band structure and an effective one dimensional potential is added so as to include the effect of the Na order. We treat the Coulomb interaction on a Co site: the intra- and inter-orbital direct terms U and U', the exchange coupling J and the pair-transfer, within the Hartree-Fock approximation. It is found that the metallic antiferromagnetic order takes place for T-c2 &lt; T &lt; T-c1 and the coexistent state of the antiferromagnetic, orbital and charge orders takes place for T &lt; T-c2 where the system becomes insulator. The obtained results are consistent with the successive phase transitions observed in Na0.5CoO2

    DOI: 10.1088/1742-6596/200/1/012233

    Web of Science

    researchmap

  • Superconductivity in a Two-Orbital Hubbard Model with Electron and Hole Fermi Pockets: Application in Iron Oxypnictide Superconductors Reviewed

    Kazuhiro Sano, Yoshiaki Ono

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   78 ( 12 )   124706-1 - 124706-5   2009.12

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:PHYSICAL SOC JAPAN  

    We investigate the electronic states of a one-dimensional two-orbital Hubbard model with band splitting by the exact diagonalization method. The Luttinger liquid parameter K-rho is calculated to obtain superconducting (SC) phase diagram as a function of on-site interactions: the intra- and inter-orbital Coulomb U and U', the Hund coupling J, and the pair transfer J'. In this model, electron and hole Fermi pockets are produced when the Fermi level crosses both the upper and lower orbital bands. We find that the system shows two types of SC phases, the SC I for U &gt; U' and the SC II for U &lt; U', in the wide parameter region including both weak and strong correlation regimes. Pairing correlation functions indicate that the most dominant pairing for the SC I (SC II) is the intersite (on-site) intraorbital spin-singlet with (without) sign reversal of the order parameters between two Fermi pockets. The result of the SC I is consistent with the sign-reversing s-wave pairing that has recently been proposed for iron oxypnictide superconductors.

    DOI: 10.1143/JPSJ.78.124706

    Web of Science

    researchmap

  • Structural Transition of Li2RuO3 Induced by Molecular-Orbit Formation Reviewed

    Yoko Miura, Masatoshi Sato, Youichi Yamakawa, Tatsuro Habaguchi, Yoshiaki Ono

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   78 ( 9 )   094706-1 - 094706-5   2009.9

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:PHYSICAL SOC JAPAN  

    A pseudo honeycomb system Li2RuO3 exhibits a second-order-like transition at temperature T = T-c similar to 540 K to a low-T nonmagnetic phase with a significant lattice distortion forming Ru-Ru pairs. For this system, we have calculated the band structure, using the generalized gradient approximation (GGA) in both the high- and low-T phases, and found that the results of the calculation can naturally explain the insulating behavior observed in the low-T phase. The detailed characters of the Ru 4d t(2g) bands obtained by the tight-binding fit to the calculated dispersion Curves show clear evidence that the structural transition is driven by the formation of the Ru-Ru molecular orbit, as proposed in our previous experimental studies.

    DOI: 10.1143/JPSJ.78.094706

    Web of Science

    researchmap

  • Quadrupole Susceptibility and Elastic Softening due to a Vacancy in Silicon Crystal Reviewed

    Takemi Yamada, Youichi Yamakawa, Yoshiaki Ono

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   78 ( 5 )   054702-1 - 054702-6   2009.5

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:PHYSICAL SOC JAPAN  

    We investigate the electronic states around a single vacancy in silicon crystal by using the Green's function approach. The triply degenerate vacancy states within the band gap are found to be extended over a large distance similar to 20 angstrom from the vacancy site and contribute to the reciprocal temperature dependence of the quadrupole susceptibility resulting in the elastic softening at low temperture. The Curie constant of the quadrupole susceptibility for the trigonal mode (O-yz, O-zx, O-xy) is largely enhanced as compared to that for the tetragonal mode (O-2(0), O-2(2)). The obtained results are consistent with the recent ultrasonic experiments in silicon crystal down to 20 mK. We also calculate the dipole and octupole susceptibilities and find that the octupole susceptibilities are extremely enhannced for a specific mode.

    DOI: 10.1143/JPSJ.78.054702

    Web of Science

    researchmap

  • Cluster Model Calculations for Charge States of a Silicon Vacancy Reviewed

    Youichi Yamakawa, Yoshiaki Ono

    25TH INTERNATIONAL CONFERENCE ON LOW TEMPERATURE PHYSICS (LT25), PART 4   150 ( 4 )   042233-1 - 042233-4   2009

     More details

    Language:English   Publishing type:Research paper (international conference proceedings)   Publisher:IOP PUBLISHING LTD  

    To investigate the charge states of a silicon vacancy, we introduce a cluster model which includes both the Coulomb interaction U between electrons in the dangling bond and the coupling g between the electrons and Jahn-Teller phonons, and solve the model by using the numerical diagonalization method. It is found that, for U &gt; 0 and g = 0, the ground state of the neutral charge state V-0 is spin singlet (S = 0) and orbital doublet. When g is varied for a finite U, the ground state changes to the orbital triplet state with S = 1 at an intermediate coupling g(c1), and finally changes to the orbital triplet state with S = 0 at a strong coupling g(c2). The obtained result for g &gt; g(c2) is consistent with the low temperature elastic softening observed in non-doped crystalline silicon.

    DOI: 10.1088/1742-6596/150/4/042233

    Web of Science

    researchmap

  • Antiferromagnetic, charge and orbital ordered states of Na0.5CoO2 based on the two-dimensional triangular lattice d-p model Reviewed

    Youichi Yamakawa, Yoshiaki Ono

    JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS   69 ( 12 )   3349 - 3351   2008.12

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:PERGAMON-ELSEVIER SCIENCE LTD  

    We investigate the electronic state of a CoO2 plane in the layered cobalt oxides NaxCoC2. using the 11 band d-p model on a two-dimensional triangular lattice, where the tight-binding parameters are determined so as to fit the LIDA band structure. Effects of the Coulomb interaction at a Co site: the intraand inter-orbital direct terms U and U&apos;, the exchange coupling J and the pair-transfer J&apos;. are treated within the Hartree-Fock approximation. We also consider the effect of the Na order at x = 0.5, where Na ions form one-dimensional chains, by taking into account of an effective one-dimensional potential Delta epsilon(d). It is found that the one-dimensional Na order enhances the Fermi surface nesting and antiferromagnetism is caused which is suppressed due to the frustration effect in the case without the Na, order. Furthermore, we consider the effect of the Coulomb interaction between the nearest-neighbor Co sites V and find that a coexistence of the magnetic, charge and orbital ordered states takes place for V&gt;V-c, where the system becomes insulator. (C) 2008 Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.jpcs.2008.06.128

    Web of Science

    researchmap

  • Effect of ferromagnetic spin fluctuations on the electronic states in NaxCoO2 based on two-dimensional triangular lattice 11-band d-p model Reviewed

    Yuki Yanagi, Yoshiaki Ono

    JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS   69 ( 12 )   3317 - 3320   2008.12

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:PERGAMON-ELSEVIER SCIENCE LTD  

    Electronic states of the CoO2 plane in NaxCoO2 are investigated on the basis of the triangular lattice 11-band d-p model by using the second order perturbation (SOP) and the random phase approximation (RPA). Due to the effect of the in-plane ferromagnetic fluctuations enhanced for 0.6 less than or similar to x less than or similar to 0.75, the quasiparticle dispersion near the Gamma-point is strongly reduced to yield an almost flat dispersion just above the fermi level. With increasing x, the electronic specific heat coefficient gamma increases towards the critical doping x(c)similar to 0.75 above which the in-plane ferromagnetism takes place. We also find that the six small hole pockets near the K-point are stabilized due to the electron correlation effect within both the SOP and the RPA. (C) 2008 Published by Elsevier Ltd

    DOI: 10.1016/j.jpcs.2008.06.078

    Web of Science

    researchmap

  • Magnetism and Superconductivity in the Two-Dimensional 16-Band d-p Model for Iron-Based Superconductors Reviewed

    Yuki Yanagi, Youichi Yamakawa, Yoshiaki Ono

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   77 ( 12 )   123701-1 - 123701-4   2008.12

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:PHYSICAL SOC JAPAN  

    The electronic states of the Fe2As2 plane in iron-based superconductors are investigated oil the basis of the two-dimensional 16-band d-p model Which includes file Coulomb interaction oil a Fe site: the intra-and inter-orbital direct terms U and U', the Hand's coupling J and the pair-transfer J'. Using the random phase approximation (RPA), we obtain the magnetic phase diagram including the stripe and the incommensurate order on the U'-J plane. We also solve the superconducting gap equation within the RPA and find that, for large J, the most favorable pairing symmetry is extended s-wave whose order parameter changes its sign between the hole pockets and the electron pockets, while it is d(xy)-wave for small J.

    DOI: 10.1143/JPSJ.77.123701

    Web of Science

    researchmap

  • Dynamical mean-field study of the heavy-fermion state in the multi-orbital Anderson lattice model coupled with Jahn-Teller phonons Reviewed

    K. Masumotoa, Y. Ono

    PHYSICA B-CONDENSED MATTER   403 ( 5-9 )   859 - 861   2008.4

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:ELSEVIER SCIENCE BV  

    We investigate the two-orbital Anderson lattice model which includes both the Coulomb interaction between f-electrons and the electron-phonon coupling between f-electrons and Jahn-Teller phonons, The model is solved by using the dynamical mean-field theory in conjunction with the exact diagonalization method. It is found that the heavy fermion state is realized due to the effect of cooperation between the Coulomb interaction and the electron-phonon coupling. Remarkably, the enhancement of lattice fluctuation and the phonon softening observed in the strong coupling regime are largely enhanced due to the Coulomb interaction in contrast to the case with the single-orbital Anderson lattice model. (c) 2007 Published by Elsevier B.V.

    DOI: 10.1016/j.physb.2007.10.047

    Web of Science

    researchmap

  • Effects of Electron Correlation and Electron-phonon Coupling on the quantum state of a Silicon Vacancy Reviewed

    Youichi Yamakawa, Keisuke Mitsumoto, Yoshiaki Ono

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   77 ( Suppl. A )   266 - 268   2008.1

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:PHYSICAL SOC JAPAN  

    Recently, Goto et al. have discovered an anomalous elastic softening due to the vacancy in the crystalline silicon at low temperature by using the ultrasonic measurements. To investigate the quantum state of the silicon vacancy, we introduce a cluster model which includes both the Coulomb interaction between electrons in the dangling bond and the coupling between the electrons and Jahn-Teller phonons. We solve the model by using the numerical diagonalization method and find that the V-0 state with neutral charge shows a transition from S=0 to S=1 in the strong coupling regime. Remarkably, the V+ state with S = 1/2 becomes stable due to the trigonal phonon while unstable due to the tetragonal phonon. The obtained result with the trigonal phonon is consistent with the elastic softening in the B-doped silicon.

    DOI: 10.1143/JPSJS.77SA.266

    Web of Science

    researchmap

  • Electronic states and pairing symmetry in the two-dimensional 16 band d-p model for iron-based superconductor Reviewed

    Yuki Yanagi, Youichi Yamakawa, Yoshiaki Ono

    Journal of the Physical Society of Japan   77 ( C )   149 - 150   2008

     More details

    Language:English   Publishing type:Research paper (international conference proceedings)   Publisher:Physical Society of Japan  

    The electronic states of the FeAs plane in iron-based superconductors are investigated on the basis of the two-dimensional 16-band d-p model, where the tight-binding parameters are determined so as to fit the band structure obtained by the density functional calculation for LaFeAsO. The model includes the Coulomb interaction on a Fe site: the intra- and inter-orbital direct terms U and U′, the exchange coupling J and the pair-transfer J′. Within the random phase approximation (RPA), we discuss the pairing symmetry of possible superconducting states including s-wave and d-wave pairing on the U′-J plane. ©2008 The Physical Society of Japan.

    DOI: 10.1143/JPSJS.77SC.149

    Scopus

    researchmap

  • Superconductivity and spin gap in the zigzag-chain t-j model simulating a CuO double chain in Pr2Ba4CU7O15-delta Reviewed

    Kazuhiro Sano, Yoshiaki Ono

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   76 ( 11 )   113701-1 - 113701-4   2007.11

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:PHYSICAL SOC JAPAN  

    Using the numerical diagonalization method, we examine the one-dimensional t(1)-t(2)-J(1)-J(2) model (zigzag-chain t-J model) which is an effective model for metallic CuO double chains in the superconductor Pr2Ba4Cu7O15-delta. Based on the Tomonaga-Luttinger liquid theory, we calculate the Luttinger liquid parameter K, as a function of the electron density n. It is found that superconductivity is realized in the parameter region, which is in accordance with experimental results. We show the phase diagram of a spin gap in the t(2)/vertical bar t(1)vertical bar-n plane by analyzing the expectation value of the twist operator Z(sigma) in the spin sector. The spin gap appears in the region with a large t(2)/vertical bar t(1)vertical bar, where the phase boundary at half filling is consistent with that of the known frustrated quantum spin system. The analysis also suggests that the estimated value of the spin gap reaches similar to 100K in the realistic parameter region of Pr2Ba4Cu7O15-delta.

    DOI: 10.1143/JPSJ.76.113701

    Web of Science

    researchmap

  • Electronic states and metal-insulator transition in the triangular lattice d-p model for layered cobaltates Reviewed

    Yoshiaki Ono

    PHYSICA C-SUPERCONDUCTIVITY AND ITS APPLICATIONS   460   1047 - 1048   2007.9

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:ELSEVIER SCIENCE BV  

    We investigate the electronic state of the I I band d-p model on the two-dimensional triangular lattice simulating a CoO2 plane in the layered cobalt oxides such as NaxCoO2 and NaxCoO2 center dot yH(2)O. The tight-binding parameters are determined so as to fit the LDA band structure. Using the slave boson approach together with the 1/N expansion method, we obtain the renormalized quasiparticle bands, where the a(1g) band with a large hole Fermi surface is largely renormalized due to the strong correlation effect, while the e'(g) bands with six hole pockets are almost unchanged. We also discuss the metal-insulator transition (MIT) with varying the d-p charge transfer energy Delta, and find that the MIT takes place at a critical value Delta(c) = 4.01 eV. (c) 2007 Elsevier B.V. All rights reserved.

    DOI: 10.1016/j.physc.2007.03.212

    Web of Science

    researchmap

  • Electronic state of NaxCoO2 based on the two-dimensional triangular lattice d-p model Reviewed

    Y. Yamakawa, Y. Ono

    JOURNAL OF PHYSICS-CONDENSED MATTER   19 ( 14 )   145289-1 - 145289-5   2007.4

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:IOP PUBLISHING LTD  

    The electronic state in a CoO2 plane of the layered cobalt oxides NaxCoO(2) is investigated by using the 11- band d - p model on a two-dimensional triangular lattice, where the tight- binding parameters are determined so as to fit the LDA band structure. The effects of the Coulomb interaction at a Co site ( the intra- and inter- orbital direct terms U and U-', the exchange coupling J and the pair- transfer J(')) are treated within the Hartree - Fock approximation. We also consider the effect of the Na order at x = 0.5, where Na ions form one- dimensional chains, by taking into account an effective one- dimensional potential Delta epsilon(d) on the CoO2 plane. It is found that the Na order enhances the Fermi surface nesting, resulting in the antiferromagnetism ( AFM) which is suppressed due to the frustration effect in the case without the Na order. When U and Delta epsilon d are varied, we observe three types of AFM: ( 1) metallic AFM with a large density of states N-F at the Fermi level for small values of U and Delta e(d), ( 2) semimetallic AFM with tiny N-F for large U with small Delta e(d), and ( 3) insulating AFM with a finite energy gap for large values of U and Delta e(d).

    DOI: 10.1088/0953-8984/19/14/145289

    Web of Science

    researchmap

  • Superconductivity in the one-dimensional two-orbital Hubbard model with finite band splitting Reviewed

    K. Sano, Y. Ono

    JOURNAL OF PHYSICS-CONDENSED MATTER   19 ( 14 )   145284-1 - 145284-6   2007.4

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:IOP PUBLISHING LTD  

    Using the numerical diagonalization method, we investigate superconductivity and related ferromagnetism in the one- dimensional two- orbital Hubbard model with a finite band splitting at less than half filling. We obtain a superconducting ( SC) region with the Luttinger liquid parameter K-rho &gt; 1 and confirm anomalous flux quantization in the SC state. It is found that the SC phase appears near the partially polarized ferromagnetic phase. We also calculate various pairing correlation functions to clarify the nature of the SC phase. Detailed analysis of these functions indicates that the triplet pairing between the nearest neighbour sites is relevant to the superconductivity. This suggests that ferromagnetic fluctuation plays an important role for the superconductivity.

    DOI: 10.1088/0953-8984/19/14/145284

    Web of Science

    researchmap

  • Ferromagnetism and superconductivity in the one-dimensional multi-orbital Hubbard model Reviewed

    Kazuhiro Sano, Yoshiaki Ono

    JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS   310 ( 2 )   E319 - E321   2007.3

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:ELSEVIER SCIENCE BV  

    Using the numerical diagonalization method, we investigate the ferromagnetism and the superconductivity in the multi-orbital Hubbard model in one-dimension. To examine the superconductivity, we calculate the critical exponent K-p, based on the Luttinger liquid theory and the anomalous flux quantization in the superconducting region. Analyzing the value of K-p, we obtain the phase diagram on the U '-J parameter plane including the superconducting phase and the fully polarized ferromagnetic phase. (c) 2006 Elsevier B.V. All rights reserved.

    DOI: 10.1016/j.jmmm.2006.10.267

    Web of Science

    researchmap

  • Charge gap in the one-dimensional extended Hubbard model at quarter filling Reviewed

    K. Sano, Y. Ono

    PHYSICAL REVIEW B   75 ( 11 )   113103-1 - 113103-4   2007.3

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:AMER PHYSICAL SOC  

    We propose a different combined approach, which consists of the exact diagonalization, renormalization group, and Bethe ansatz methods, for precise estimates of the charge gap Delta in the one-dimensional extended Hubbard model, with on-site and nearest-neighbor interactions U and V at quarter filling. This approach enables us to obtain the absolute value of Delta, including the prefactor, without ambiguity even in the critical regime of the metal-insulator transition (MIT) where Delta is exponentially small, beyond usual renormalization group methods and/or finite-size scaling approaches. The detailed results of Delta, down to the order of 10(-10) near the MIT, are shown as contour lines on the U-V plane.

    DOI: 10.1103/PhysRevB.75.113103

    Web of Science

    researchmap

  • Nonadiabatic interaction between electrons and Jahn-Teller distortions in a silicon vacancy Reviewed

    Y. Yamakawa, K. Mitsumoto, Y. Ono

    JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS   310 ( 2 )   993 - 995   2007.3

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:ELSEVIER SCIENCE BV  

    Recently, Goto et al. have discovered anomalous elastic softening due to vacancy in crystalline silicon at very low temperature. To investigate the quantum state of the silicon vacancy, we introduce a cluster model which includes the electron-lattice coupling between electrons and Jahn-Teller distortions together with the Coulomb interaction between electrons. By using the numerical diagonalization method, we take into account of both the nonadiabatic and the correlation effects. We find that the 3-fold orbital degeneracy in the ground state of a silicon vacancy is stable against the Jahn-Teller distortions because of the strong quantum fluctuation due to the nonadiabatic coupling between electrons and Jahn-Teller distortions. The obtained result is a striking contrast to the previous theoretical results within the adiabatic approximation and is consistent with the newly observed experiment. (c) 2006 Elsevier B.V. All rights reserved.

    DOI: 10.1007/j.jmmm.2006.10.414

    Web of Science

    researchmap

  • Heavy fermion state in the periodic Anderson-Holstein model away from half filling Reviewed

    K. Mitsumoto, Y. Ono

    JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS   310 ( 2 )   419 - 421   2007.3

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:ELSEVIER SCIENCE BV  

    We investigate the electronic state of the periodic Anderson-Holstein model, which includes both the electron-electron Coulomb interaction and the electron-phonon coupling, away from half filling. The model is solved by using the dynamical mean-field theory combined with the exact diagonalization method. The heavy fermion state with large effective mass due to the electron-phonon coupling is realized in the wide range of the f-electron number n(f), while that due to the Coulomb interaction is realized in the narrow range of n(f)similar to 1. (c) 2006 Elsevier B.V. All rights reserved.

    DOI: 10.1016/j.jmmm.2006.10.257

    Web of Science

    researchmap

  • Heavy fermions and rattling motions in the periodic Anderson-Holstein model Reviewed

    K Mitsumoto, Y Ono

    PHYSICA B-CONDENSED MATTER   378-80   265 - 266   2006.5

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:ELSEVIER SCIENCE BV  

    We investigate a heavy fermion behaviour and a deformation of an effective potential of the ions due to electron-phonon interaction for the periodic Anderson-Holstein model by using the dynamical mean-field theory combined with the exact diagonalization method. For the strong electron-phonon coupling, the system shows an anomalous heavy fermion behaviour with a large lattice fluctuation and an extreme phonon softening, and then an effective potential for the ions changes from a simple harmonic potential for the non-interacting case to a double-well potential for the strong electron-phonon coupling. (c) 2006 Elsevier B.V. All rights reserved.

    DOI: 10.1016/j.physb.2006.01.098

    Web of Science

    researchmap

  • Heavy fermions in the periodic Anderson model with singlet-triplet crystal-field levels Reviewed

    Y Ono, K Mitsumoto

    PHYSICA B-CONDENSED MATTER   378-80   694 - 695   2006.5

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:ELSEVIER SCIENCE BV  

    We investigate the two-orbital periodic Anderson model with f(2)-configuration by using the dynamical mean-field theory in which the effective impurity Anderson model is solved using the exact diagonalization method. The renormalization factor Z and the local moment &lt; S-2 &gt; are obtained as functions of the Coulomb interaction U, the exchange (Hund's rule) coupling J and the crystal-field splitting J. When the ionic ground state is triplet for Delta &lt;Delta(c) = 3J, the heavy fermion state with the mass enhancement m*/m = Z(-1) &gt;= 100 together with (S-2)similar to 2 is realized in the strong correlation regime for U &gt;= W, where W is the conduction bandwidth. When the ionic ground state is singlet for Delta &gt; Delta(c), m*/m similar to 1 and &lt; S-2 &gt;similar to 0 for any value of U. When the singlet ground state and the triplet excited state form a quasi-quartet for J the system shows a moderate mass enhancement m*/m similar to 10-100. (c) 2006 Elsevier B.V. All rights reserved.

    DOI: 10.1016/j.physb.2006.01.224

    Web of Science

    researchmap

  • Superconductivity in the CuO double chain of Pr2Ba4Cu7O15-delta on the basis of Tomonaga-Luttinger liquid theory Reviewed

    K Sano, Y Ono, Y Yamada

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   74 ( 11 )   2885 - 2888   2005.11

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:PHYSICAL SOC JAPAN  

    Recently, Matsukawa et al. discovered a new superconductor, Pr2Ba4Cu7O15-delta, in which metallic CuO double chains are responsible for the superconductivity. To investigate its superconductivity, we employ the d-p double chain model where the tight-binding parameters are determined so as to fit a band structure in the local density approximation (LDA). On the basis of the Tomonaga-Luttinger liquid theory, we obtain a phase diagram that includes the superconducting phase in the weak coupling limit. We also calculate the Luttinger liquid parameter K-p as a function of the electron density n using the Hartree-Fock approximation. With increasing n from quarter filling, K-p increases and then exceeds 1/2 when the superconducting correlation becomes most dominant. K-p has a maximum at an optimal density between quarter- and half-filling. These results are consistent with the experimental observation.

    DOI: 10.1143/JPSJ.74.2885

    Web of Science

    researchmap

  • Phonon softening and double-well potential formation due to electron-phonon interaction in heavy-fermion systems Reviewed

    K Mitsumoto, Y Ono

    PHYSICA C-SUPERCONDUCTIVITY AND ITS APPLICATIONS   426   330 - 334   2005.10

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:ELSEVIER SCIENCE BV  

    We investigate the periodic Anderson-Holstein model by using the dynamical mean-field theory combined with the exact diagonalization method. For the strong electron-phonon coupling g greater than or similar to g(c), the system shows an anomalous heavy-fermion behaviour which is accompanied by a large lattice fluctuation and an extreme phonon softening. We also calculate an effective potential for the ions and find that a simple harmonic potential for g g, changes into a double-well potential for g greater than or similar to g(c). The effective pairing interaction between the conduction electrons shows a maximum at g approximate to g(c) where the superconducting transition temperature is expected to be maximum. (c) 2005 Elsevier B.V. All rights reserved.

    DOI: 10.1016/j.physc.2004.12.021

    Web of Science

    researchmap

  • Phase diagram and dynamic response functions of the Holstein-Hubbard model Reviewed

    W Koller, D Meyer, AC Hewson, Y Ono

    PHYSICA B-CONDENSED MATTER   359   795 - 797   2005.4

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:ELSEVIER SCIENCE BV  

    We present the phase diagram and dynamical correlation functions for the Holstein-Hubbard model at half-filling and at zero temperature. The calculations are based on the dynamical mean field theory (DMFT). The effective impurity model is solved using exact diagonalization (ED) and the numerical renormalization group (NRG). Excluding long-range order, we find three different paramagnetic phases, metallic, bipolaronic and Mott insulating, depending on the Hubbard interaction U and the electron-phonon coupling g. We present the behaviour of the one-electron spectral functions and phonon spectra close to the metal-insulator transitions. (c) 2005 Elsevier B.V. All rights reserved.

    DOI: 10.1016/j.physb.2005.01.230

    Web of Science

    researchmap

  • Critical behavior near the metal-insulator transition in the one-dimensional extended Hubbard model at quarter filling Reviewed

    K Sano, Y Ono

    PHYSICAL REVIEW B   70 ( 15 )   155102-1 - 155102-7   2004.10

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:AMER PHYSICAL SOC  

    We examine the critical behavior near the metal-insulator transition (MIT) in the one-dimensional extended Hubbard model with the on-site and the nearest-neighbor interactions U and V at quarter filling using a combined method of the numerical diagonalization and the renormalization group (RG). The Luttinger-liquid parameter K-rho is calculated with the exact diagonalization for finite size systems and is substituted into the RG equation as an initial condition to obtain K-rho in the infinite size system. This approach also yields the charge gap Delta in the insulating state near the MIT. The results agree very well with the available exact results for U=infinity even in the critical regime of the MIT where the characteristic energy becomes exponentially small and the usual finite size scaling is not applicable. When the system approaches the MIT critical point V--&gt;V-c for a fixed U, K-rho and Delta behave as \lnDelta\(-2)=c(Delta)(V/V-c-1) and (K-rho-1/4)(2)=c(K)(1-V/V-c), where the critical value V-c and the coefficients c(Delta) and c(K) are functions of U. These critical properties, which are known to be exact for U=infinity, are observed also for finite U case. We also observe the same critical behavior in the limit of the MIT critical point U--&gt;U-c when U is varied for a fixed V.

    DOI: 10.1103/PhysRevB.70.155102

    Web of Science

    researchmap

  • First- and second-order phase transitions in the Holstein-Hubbard model Reviewed

    W Koller, D Meyer, Y Ono, AC Hewson

    EUROPHYSICS LETTERS   66 ( 4 )   559 - 564   2004.5

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:E D P SCIENCES  

    We investigate metal-insulator transitions in the half-filled Holstein-Hubbard model as a function of the on-site electron-electron interaction U and the electron-phonon coupling g. We use several different numerical methods to calculate the phase diagram, the results of which are in excellent agreement. When the electron-electron interaction U is dominant, the transition is to a Mott insulator; when the electron-phonon interaction dominates, the transition is to a localized bipolaronic state. In the former case, the transition is always found to be second order. This is in contrast to the transition to the bipolaronic state, which is clearly first order for larger values of U. We also present results for the quasiparticle weight and the double occupancy as functions of U and g.

    DOI: 10.1209/epl/i2003-10228-6

    Web of Science

    researchmap

  • Nonlinear sigma model method for the J(1)-J(2) Heisenberg model: Disordered ground state with plaquette symmetry Reviewed

    K Takano, Y Kito, Y Ono, K Sano

    PHYSICAL REVIEW LETTERS   91 ( 19 )   197202-1 - 197202-4   2003.11

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:AMER PHYSICAL SOC  

    A novel nonlinear sigma model method is proposed for the two-dimensional J(1)-J(2) model, which is extended to include plaquette-type distortion. The nonlinear sigma model is properly derived without spoiling the original spin degrees of freedom. The method shows that a single disordered phase continuously extends from a frustrated uniform regime to an unfrustrated distorted regime. By the continuity and Oshikawa&apos;s commensurability condition, the disordered ground states for the uniform J(1)-J(2) model are plaquette states with fourfold degeneracy.

    DOI: 10.1103/PhysRevLett.91.197202

    Web of Science

    researchmap

  • Ferromagnetism and superconductivity in the multi-orbital Hubbard model: Hund's rule coupling versus crystal-field splitting Reviewed

    K Sano, Y Ono

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   72 ( 8 )   1847 - 1850   2003.8

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:PHYSICAL SOC JAPAN  

    The multi-orbital Hubbard model in one dimension is studied using the numerical diagonalization method. Due to them effect of crystal-field splitting Delta, the fully polarized ferromagnetism, which is observed in the strong coupling regime, becomes unstable against the partially polarized ferromagnetism when Hund's rule coupling J is smaller than a certain critical value of order of Delta. In the vicinity of the partially polarized ferromagnetism, the orbital fluctuation develops due to the competition between Hund's rule coupling and crystal-field splitting. The superconducting phase with the Luttinger liquid parameter K-rho &gt; 1 is observed for the singlet ground state in this region.

    DOI: 10.1143/JPSJ.72.1847

    Web of Science

    researchmap

  • Mott transition in the multi-band Hubbard model in infinite dimensions Reviewed

    Y Ono, R Bulla, M Potthoff

    PHYSICA B-CONDENSED MATTER   329   942 - 943   2003.5

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:ELSEVIER SCIENCE BV  

    The Mott metal-insulator transition in the multi-band Hubbard model in infinite dimensions is studied by using the linearized dynamical mean-field theory. The critical interaction U-c is obtained analytically. For the symmetric case and for orbital degeneracy M we find U-c = (4M + 2)rootL(2) where L-2 is the second moment of the non-interacting density of states. We also derive an analytical expression for the discontinuity of the chemical potential mu(n) at the filling n = M for U &gt; U-c. The findings are in good agreement with numerical results obtained from the exact diagonalization method. (C) 2003 Published by Elsevier Science B.V.

    DOI: 10.1016/S0921-4526(02)02613-3

    Web of Science

    researchmap

  • Unambiguous relationship between the Hubbard, t-J and d-p models in one-dimension based on the Luttinger liquid theory Reviewed

    Y Sano, Y Ono

    PHYSICA C-SUPERCONDUCTIVITY AND ITS APPLICATIONS   388   84 - 85   2003.5

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:ELSEVIER SCIENCE BV  

    We examine the one-dimensional (ID) d-p model in comparison with typical 1D models such as the 1D Hubbard model and the 1D t-J model using the numerical diagonalization method combined with the Luttinger liquid theory. We calculate the spin velocity nu(sigma), the charge velocity nu(rho) and the Luttinger liquid parameter K-rho for each model. Using these parameters, a relationship between the models is obtained unambiguously. We find that the d-p model can be described by the Hubbard model in the wide parameter region, while it can be described by the t-J model only in the strong coupling limit. (C) 2003 Elsevier Science B.V. All rights reserved.

    DOI: 10.1016/S0921-4534(02)02662-X

    Web of Science

    researchmap

  • Mott transitions in correlated electron systems with orbital degrees of freedom Reviewed

    Y Ono, M Potthoff, R Bulla

    PHYSICAL REVIEW B   67 ( 3 )   035119-1 - 035119-6   2003.1

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:AMERICAN PHYSICAL SOC  

    Mott metal-insulator transitions in an M-fold orbitally degenerate Hubbard model are studied by means of a generalization of the linearized dynamical mean-field theory. The method allows for an efficient and reliable determination of the critical interaction U-c for any integer filling n and different M at zero temperature. For half filling a linear dependence of U-c on M is found. Inclusion of the (full) Hund's rule exchange J results in a strong reduction of U-c. The transition turns out to change qualitatively from continuous for J=0 to discontinuous for any finite J. This result is confirmed using the exact-diagonalization method for M=2.

    DOI: 10.1103/PhysRevB.67.035119

    Web of Science

    researchmap

  • Effective Interactions of the One-Dimensional d-p Model Based on the Luttinger Liquid Theory Reviewed

    K. Sano, Y. Ono

    Journal of the Physical Society of Japan   71 ( Suppl. )   353 - 355   2002.12

     More details

    Language:English   Publishing type:Research paper (other academic)   Publisher:The Physical Society of Japan  

    We examine the 1D <italic>d</italic>–<italic>p</italic>model in comparison with a typical one-dimensional (1D) model such as the Hubbard model or the <italic>t</italic>–<italic>J</italic>model by the numerical diagonalization method combined with the Luttinger liquid theory. We calculate the Luttinger liquid parameter <italic>K</italic><sub>ρ</sub>and the ratio of the spin velocity and the charge velocity <italic>v</italic><sub>s</sub>/<italic>v</italic><sub>c</sub>for the three models. Analysis of these values gives the relationship between those models without ambiguity. We find that the <italic>d</italic>–<italic>p</italic>model is similar to not the <italic>t</italic>–<italic>J</italic>model but the Hubbard model for wide range of the parameters. Though the repulsion of the <italic>d</italic>–<italic>p</italic>model at Cu-sites is very strong, the Hubbard model corresponding to the <italic>d</italic>–<italic>p</italic>model has relatively weak repulsion for the small charge-transfer energy.

    DOI: 10.1143/JPSJS.71S.353

    CiNii Article

    CiNii Books

    researchmap

    Other Link: http://hdl.handle.net/10191/26841

  • Metal-insulator transition of the one-dimensional U-V model at quarter filling Reviewed

    K Sano, Y Ono

    JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS   63 ( 6-8 )   1567 - 1570   2002.6

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:PERGAMON-ELSEVIER SCIENCE LTD  

    The metal-insulator (M-I) transition of the one-dimensional extended Hubbard model with both on-site U and nearest neighbor V interactions is studied by a combination of the numerical diagonalization and the renormalization group (RG) method. We diagonalize finite size systems numerically and calculate the Luttinger-liquid parameter K-p. Substituting the numerical result to the RG equations as the initial condition, we explicitly calculate the renormalized K-p and the renormalized umklapp scattering parameter G. This approach gives the critical properties of the K-p and the charge gap near the M-I transition beyond the usual finite-size scaling for the numerical diagonalization result. We also obtain a contour map of the charge gap by the numerical diagonalization method on the U-V plain. (C) 2002 Elsevier Science Ltd. All rights reserved.

    DOI: 10.1016/S0022-3697(02)00104-X

    Web of Science

    researchmap

  • Effect of Direct Transfer on Critical Behaviour of Mott Transition in the two-Band Hubbard model Reviewed

    Yasuo Ohashi, Yoshiaki Ono

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   71 ( Suppl. )   217 - 219   2002.1

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:PHYSICAL SOC JAPAN  

    The Mott metal-insulator transition in the two-band ifubbard model in infinite dimensions is studied by using the linearized dynamical mean-field theory. The discontinuity in the chemical potential for the change from hole to electron doping is calculated analytically as a function of the on-site Coulomb interaction U, and the charge-transfer energy Delta between the d- and p-orbitals, transfer integrals t(pd), t(pp), t(dd) between p-d, p-p and d-d sites respectively. The critical behaviour of the quasiparticle weight is also obtained analytically.

    DOI: 10.1143/JPSJS.71S.217

    Web of Science

    researchmap

  • Magnetism and Superconductivity in a Two-band Hubbard Model in Infinite Dimensions Reviewed

    Yoshiaki Ono, Kazuhiro Sano

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   71 ( Suppl. )   356 - 358   2002.1

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:PHYSICAL SOC JAPAN  

    We study a two-band Hubbard model using the dynamical mean-field theory combined with the exact diagonalization method. At the electron density n=2, a transition from a band insulator to a correlated semimetal occurs when the on-site Coulomb interaction U is varied for a fixed value of the charge-transfer energy A. At, low temperature, the correlated semimetal shows ferromagnetism or superconductivity. With increasing doping In 2', the ferromagnetic transition temperature rapidly decreases and finally bet owes zero at a critical value of n. The second-order phase transition occUTS at high temperature, while a phase separation of ferromagnetic and paramagnetic states takes place at low temperature. The superconducting transition temperature gradually decreases and finally becomes zero near a =3) where the system is Mott insulator which shows antiferromagnetism at low temperature.

    DOI: 10.1143/JPSJS.71S.356

    Web of Science

    researchmap

  • Critical behaviour near the Mott metal-insulator transition in a two-band Hubbard model Reviewed

    Y Ohashi, Y Ono

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   70 ( 10 )   2989 - 2998   2001.10

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:PHYSICAL SOC JAPAN  

    The Mott metal insulator transition in the two-band Hubbard model in infinite dimensions is studied by using the linearized dynamical mean-field theory. The discontinuity in the chemical potential for the change from hole to electron doping is calculated analytically as a function of the on-site Coulomb interaction U at the d-orbital and the charge-transfer energy Delta between the d-and p-orbitals. Critical behaviour of the quasiparticle weight is also obtained analytically as a function of U and Delta. The analytic results are in good agreement with the numerical results of the exact diagonalization method.

    DOI: 10.1143/JPSJ.70.2989

    Web of Science

    researchmap

  • Critical behaviour near the metal-insulator transition of a doped Mott insulator Reviewed

    Y Ono, R Bulla, AC Hewson, M Potthoff

    EUROPEAN PHYSICAL JOURNAL B   22 ( 3 )   283 - 290   2001.8

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:SPRINGER-VERLAG  

    We have studied the critical behaviour of a doped Mott insulator near the metal-insulator transition for the infinite-dimensional Hubbard model using a linearized form of dynamical mean-field theory. The discontinuity in the chemical potential in the change from hole to electron doping. for U larger than a critical value U-c, has been calculated analytically and is found to be in good agreement with the results of numerical methods. We have also derived analytic expressions for the compressibility, the quasiparticle weight. the double occupancy and the local spin susceptibility near half-filling as functions of the on-site Coulomb interaction and the doping.

    DOI: 10.1007/PL00011147

    Web of Science

    researchmap

  • Renormalization group approaches to strongly correlated electron systems Invited Reviewed

    AC Hewson, SC Bradley, R Bulla, Y Ono

    INTERNATIONAL JOURNAL OF MODERN PHYSICS B   15 ( 19-20 )   2549 - 2567   2001.8

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:WORLD SCIENTIFIC PUBL CO PTE LTD  

    In recent years the numerical renormalization group (NRG) method has been extended to the calculation of dynamic response functions and transport properties of magnetic impurity models. The approach can now be applied more widely to lattice models of strongly correlated electron systems by the use of dynamical mean field theory (DMFT), in which the lattice problem is transformed into one for an effective impurity with an additional self-consistency constraint. We review these developments and assess the potential for further applications of this approach. We also discuss an alternative approach to renormalization, renormalized perturbation theory, in which the leading asymptotically exact results for the low temperature regime for a number of magnetic impurity models can be obtained within finite order perturbation theory.

    DOI: 10.1142/S0217979201006367

    Web of Science

    researchmap

  • Phase diagram of the Mott transition in a two-band Hubbard model in infinite dimensions Reviewed

    Y Ono, R Bulla, AC Hewson

    EUROPEAN PHYSICAL JOURNAL B   19 ( 3 )   375 - 384   2001.2

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:SPRINGER-VERLAG  

    The Mott metal-insulator transition in the two-band Hubbard model in infinite dimensions is studied by using the linearized dynamical mean-field theory recently developed by Bulla and Potthoff. The phase boundary of the metal-insulator transition is obtained analytically as a function of the on-site Coulomb interaction at the d-orbital, the charge-transfer energy between the d- and p-orbitals and the hopping integrals between p-d, d-d and p-p orbitals. The result is in good agreement with the numerical results obtained from the exact diagonalization method.

    DOI: 10.1007/s100510170313

    Web of Science

    researchmap

  • Metal-insulator transition of the one-dimensional extended Hubbard model Reviewed

    K Sano, Y Ono

    JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS   62 ( 1-2 )   281 - 284   2001.1

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:PERGAMON-ELSEVIER SCIENCE LTD  

    Metal-insulator transition of the one-dimensional Hubbard model with both on-site U and nearest neighbor V interactions is studied by a combination of the numerical diagonalization method and the renormalization group (RG) method. Substituting the numerical result to the RG equation as the initial condition, we calculate the Luttinger-liquid parameter K-p at quarter tilling. Comparing the renormalized K-p with the known exact result, we find it to be reliable in the strong coupling regime. This approach gives an evident critical point of the metal-insulator transition beyond the usual finite-size scaling for the numerical diagonalization result. The charge gap is also estimated by the numerical diagonalization method in the insulator region. (C) 2000 Elsevier Science Ltd. All rights reserved.

    DOI: 10.1016/S0022-3697(00)00146-3

    Web of Science

    researchmap

  • Mott transition and superconductivity in the two-band Hubbard model in infinite dimensions Reviewed

    Y Ono, K Sano

    JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS   62 ( 1-2 )   285 - 288   2001.1

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:PERGAMON-ELSEVIER SCIENCE LTD  

    Electronic states in the two-band Hubbard model with infinite dimensions are investigated by using the exact diagonalization method. In the half-filled case, the boundary separating the metallic and the insulating regimes is calculated as the function of the on-site repulsive interaction U and the charge-transfer energy Delta. The metal-insulator transition of Mott-Hubbard type is obtained for U &lt; &lt;Delta&gt; while that of charge-transfer type is obtained for U &gt; Delta. In the doped case, on-site paring susceptibility is calculated at finite temperature. The critical temperature of the superconductivity is found in a charge-transfer type but not in a Mott-Hubbard type. (C) 2000 Elsevier Science Ltd. All rights reserved.

    DOI: 10.1016/S0022-3697(00)00147-5

    Web of Science

    researchmap

  • Non-Fermi liquid and Mott transition in the multi-channel two-band Hubbard model in infinite dimensions Reviewed

    Y Ono, A Tsuruta, T Matsuura, Y Kuroda

    PHYSICA B   281   410 - 411   2000.6

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:ELSEVIER SCIENCE BV  

    Electronic states in the single- and multi-channel two-band Hubbard models in infinite spatial dimensions are investigated by using the self-consistent 1/N-expansion method which is a conserving approximation based on the perturbation expansion from the large limit of the spin-orbital degeneracy N. It is shown that a metallic state in the single-channel model behaves as a Fermi liquid. where imaginary part of self-energy of quasi-particles is proportional to omega(2) + (pi T)(2). while a metallic stare in the multi-channel model behaves as a non-Fermi liquid, where the imaginary part of the self-energy is finite even at omega = T = 0. In each model with a half-filled band the Mott metal-insulator transition (MIT) is observed. when the charge transfer energy Delta is varied. When the system approaches the MIT point. effective mass of quasi-particles diverges in the single-channel model, while the total number of quasi-particles becomes zero in the multi-channel model. (C) 2000 Elsevier Science B.V. All rights reserved.

    DOI: 10.1016/S0921-4526(99)00924-2

    Web of Science

    researchmap

  • Fermi liquid and non-Fermi liquid in M-channel: N fold degenerate Anderson lattice Reviewed

    A Tsuruta, A Kobayashi, K Deguchi, Y Ono, T Matsuura, Y Kuroda

    PHYSICA B   281   408 - 409   2000.6

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:ELSEVIER SCIENCE BV  

    We investigate electronic states in the M-channel N fold degenerate Anderson lattice with the help of 1/N-expansion. In the single-channel case, we showed that the imaginary part of the self-energy of the conduction electrons up to O(N-2) is exactly given by a Form of the Fermi-liquid-type. In the multichannel case, we find a T-linear term of O(N-1) in the imaginary part of the self-energy of the conduction electrons, in contrast to a constant term found in the infinite dimensions. Then we critically examine the results obtained in the infinite dimensions. (C) 2000 Elsevier Science B.V. All rights reserved.

    DOI: 10.1016/S0921-4526(99)00998-9

    Web of Science

    researchmap

  • Non-Fermi liquid in multichannel degenerate Anderson lattice Reviewed

    A Tsuruta, A Kobayashi, Y Ono, T Matsuura, Y Kuroda

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   68 ( 8 )   2491 - 2494   1999.8

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:PHYSICAL SOCIETY JAPAN  

    We investigate electronic states in the multichannel degenerate Anderson lattice with the aid of the 1/N-expansion procedure. Inclusion of the self-energy in O(N-0) leads to heavy electrons with degeneracy of channel and spin-orbit. In O(N-1); we find a T-linear term in the imaginary part of the self-energy of the conduction electrons at the Fermi level, in contrast to a T-2-term as in the Fermi liquid or a constant term as in the non-Fermi liquid found in infinite dimensions. The disappearance of the imaginary Dart at T = O is due to the intersite correlation effects that reflect the translational invariance. The Luttinger sum rule is proved to hold.

    DOI: 10.1143/JPSJ.68.2491

    Web of Science

    researchmap

  • Fermi liquid in degenerate Anderson lattice Reviewed

    A Tsuruta, A Kobayashi, K Deguchi, Y Ono, T Matsuura, Y Kuroda

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   68 ( 4 )   1067 - 1070   1999.4

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:PHYSICAL SOC JAPAN  

    We investigate the Fermi liquid in the infinite-U degenerate Anderson lattice using expansion from the limit of large spin-orbital degeneracy N. By collecting all diagrams up to O(N-2), we show that the imaginary part of the self-energy of the conduction electrons is given by a form proportional to (omega - mu)(2) + pi(2)T(2). We also show that the Luttlinger sum rule holds up to O(N-1). This implies that the literal 1/N-expansion procedure correctly describes the Fermi liquid in the U-infinite Anderson lattice.

    DOI: 10.1143/JPSJ.68.1067

    Web of Science

    researchmap

  • Superconductivity of the one-dimensional d-p model with p-p transfer. II Reviewed

    K Sano, Y Ono

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   67 ( 12 )   4151 - 4156   1998.12

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:PHYSICAL SOC JAPAN  

    We investigate the one-dimensional d-p model with the transfer energy t(pp) between the nearest neighbor p sites by the numerical diagonalization method. By calculating the critical exponent K-rho based on the Luttinger liquid relations and the paring correlation functions, we analyze the superconducting state induced by the effect of the large repulsion U-d at the Cu site in cooperation with the transfer energy t(pp). We obtain a phase diagram of the superconducting region on the filling n vs. U-d parameter plane. It shows that the superconducting region appears when U-d is larger than a certain critical value which decreases with increasing n. The results of paring correlation functions suggest that a singlet paring between the nearest neighbor p sites is most relevant to the superconductivity. We also discuss a relationship between the d-p model and the t-J model through an analysis of the dependence of K-rho on the parameters.

    DOI: 10.1143/JPSJ.67.4151

    Web of Science

    researchmap

  • Theory of metamagnetism in the heavy fermion compound CeRu2Si2 Reviewed

    Y Ono

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   67 ( 7 )   2197 - 2200   1998.7

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:PHYSICAL SOC JAPAN  

    Metamagnetism of heavy fermions is investigated using the Anderson lattice model in which the anisotropy of the hybridization matrix element, together with electron-lattice coupling, is taken into account. Within the leading-order approximation in the 1/N-expansion, it is found that the incoherent part of the f electron becomes relevant above a critical field H-M, while it is irrelevant below H-M. Consequently, both magnetization and magnetostriction show abrupt increases with increasing H at H-M. The results are in good agreement with the experimental data of CeRu2Si2.

    DOI: 10.1143/JPSJ.67.2197

    Web of Science

    researchmap

  • Infrared divergence and non-Fermi liquid in multichannel degenerate Anderson model. II. Reviewed

    A Tsuruta, Y Ono, T Matsuura, Y Kuroda

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   67 ( 7 )   2346 - 2362   1998.7

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:PHYSICAL SOC JAPAN  

    In the previous studies, we examined roles of infrared divergences in pseudo-particle spectra in the impurity Anderson models with use of the expansion from the limit of the large spin-orbital degeneracy (1/N-expansion). Here, such studies are extended to obtain renormalized forms of frequency-/temperature-dependence of physical quantities such as scattering rate of conduction electrons and spin-, pseudo-spin- and charge-susceptibility? where the pseudo-spin represents the channel's degree of freedom, hy collecting the most infrared-divergent terms in the 1/N-expansion. The results reconfirm that in single channel models the infrared divergent terms in the pseudo-particle spectra are completely cancelled hy the vertex corrections at each order of the 1/N-expansion, while in multichannel models the cancelation becomes incomplete and the terms remain in the physical quantities.

    DOI: 10.1143/JPSJ.67.2346

    Web of Science

    researchmap

  • Dynamical spin susceptibility of the d-p model in the over doping region Reviewed

    A Kobayashi, Y Ono, T Matsuura, Y Kuroda

    PHYSICA C-SUPERCONDUCTIVITY AND ITS APPLICATIONS   300 ( 3-4 )   287 - 300   1998.5

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:ELSEVIER SCIENCE BV  

    Dynamical spin susceptibility chi(s)(q, omega) of the d-p model in the over doping region is investigated by using the auxiliary boson technique. It includes higher order terms of the 1/N-expansion within the random phase approximation (RPA) of the local vertex, where frequency dependence of the quasi-particle interaction is taken into account. The incommensurate spin fluctuation is obtained due to the nesting effect in the low energy region (omega less than or similar to omega*), whereas the commensurate one in the high energy region (omega greater than or similar to omega*), the characteristic energy omega* is estimated to be about 30 meV. Both of the spin-lattice relaxation rate 1/T-l and the spin-spin relaxation rate 1/T-g monotonically increase as T decreases, while the spin Knight shift K is almost independent of T. (C) 1998 Elsevier Science B.V. All rights reserved.

    DOI: 10.1016/S0921-4534(98)00131-2

    Web of Science

    researchmap

  • Superconductivity of the one-dimensional d-p model with p-p transfer Reviewed

    K Sano, Y Ono

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   67 ( 2 )   389 - 392   1998.2

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:PHYSICAL SOC JAPAN  

    Using the numerical diagonalization method, we investigate the one-dimensional d-p model, simulating a Cu-O linear chain with strong Coulomb repulsions. Considering the effect of the transfer energy t(pp) between the nearest neighbor oxygen-sites, we calculate the critical exponent of the correlation functions K-p based on the Luttinger liquid relations and the ground state energy E-0(phi) as a function of an external flux phi. We find that the transfer t(pp) increases the charge susceptibility and the exponent K-rho in cooperation with the repulsion U-d at the Cu site. We also show that anomalous flux quantization occurs for K-rho &gt; 1. The superconducting region is presented on a phase diagram of U-d vs. t(pp) plane.

    DOI: 10.1143/JPSJ.67.389

    Web of Science

    researchmap

  • d-site substitution effects in the d-p model Reviewed

    Y Ono, K Deguchi, T Matsuura, Y Kuroda

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   67 ( 1 )   29 - 32   1998.1

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:PHYSICAL SOC JAPAN  

    Effects of d-site substitution in the d-p model simulating a CuO2-plane in high-T-c cuprates are investigated using the slave boson technique and the 1/N-expansion method. It is found that nonmagnetic impurities, e.g., Zn, substituted for Cu, strongly scatter the p-holes and drastically decrease hole densities at the neighboring O-sites. In the low doping region; the decrease reduces the Kondo temperature T-K at the neighboring Cu-sites. The repulsion U-pd between holes on the nearest neighbor Cu-and O-sites; which is known to enhance the charge susceptibility in the pure systems without impurities, turns out to promote the reduction of Tic due to the nonmagnetic impurity. Then, Cu d-spins in the vicinity of the impurity behave as local moments at temperatures higher than the reduced T-K.

    DOI: 10.1143/JPSJ.67.29

    Web of Science

    researchmap

  • Infrared divergence and non-Fermi liquid in multichannel degenerate Anderson model Reviewed

    A Tsuruta, Y Ono, T Matsuura, Y Kuroda

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   66 ( 11 )   3528 - 3535   1997.11

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:PHYSICAL SOC JAPAN  

    As a straightforward extention of the study on infrared divergences in pseudo-particle spectra in the single-channel degenerate impurity Anderson model, those of the multichannel model are examined with use of the expansion from the large limit of the spin-orbital degeneracy N. Analysis with the most divergent terms in the expansion shows that exponents of spectra of the. slave boson and the pseudo-fermion in the M-channel model with 1 less than or equal to M much less than N are given respectively by 1 - n(f)(2)M/N and (2n(f)-n(f)(2))M/N, where n(f) is the average number of localized electrons at the impurity site. When M = 1, the results recover those obtained earlier in the single channel model. In the limits, n(f) --&gt; 1 and M-2 much less than 1, these results tend to those obtained by the non-crossing approximation (NCA) study. It also shows that the scattering rate of the conduction electrons in the M-channel model includes infrared divergent terms proportional to (1 - n(f))(1 - M-2) in contrast to the absence of infrared divergent terms in the single-channel model.

    DOI: 10.1143/JPSJ.66.3528

    Web of Science

    researchmap

  • Metamagnetism and Fermi surface in the Anderson lattice model Reviewed

    Y Ono

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   65 ( 1 )   19 - 22   1996.1

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:PHYSICAL SOC JAPAN  

    We investigate magnetization as a function of external magnetic field H in the U-infinite Anderson lattice model within the leading-order approximation in the 1/N-expansion. At T = 0, at H = H-M where the Zeeman energy is equal to a certain characteristic energy of the system, the magnetization curve has a kink and the differential susceptibility dM/dH shows a jump. At finite temperature, dM/dH shows a peak around H-M. Its maximum value increases with decreasing T and saturates to a finite value at T --&gt; 0. When H &lt; H-M, the f and conduction electrons form renormalized bands with a large Fermi surface determined by the Luttinger sum On the other hand, when H &gt; H-M, the bands reform such that they are free from the Luttinger sum rule, eventually leading to a small Fermi surface at H &gt;&gt; H-M. These results are consistent with the metamagnetic properties observed in the heavy fermion compound CeRu2Si2.

    DOI: 10.1143/JPSJ.65.19

    Web of Science

    researchmap

  • IMPURITY EFFECTS IN LATTICE ANDERSON MODEL Reviewed

    K DEGUCHI, Y ONO, T MATSUURA, Y KURODA

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   64 ( 10 )   3826 - 3839   1995.10

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:PHYSICAL SOC JAPAN  

    Effects of a single impurity in the degenerate lattice Anderson model describing heavy elecron systems are investigated rigorously within the framework of the axiliary boson method and the perturbation expansion from the large limit of the spin-orbital degeneracy N(1/N-expansion). It is found that a nan-magnetic impurity leads to the unitarity limit value of the scattering rate of the conduction electrons at low temperature while it has no appreciable effect on the thermodynamic properties. These results are consistent with the experimental observations on the heavy electron systems such as Ce1-xLaxCu6.

    DOI: 10.1143/JPSJ.64.3826

    Web of Science

    researchmap

  • CHARGE SUSCEPTIBILITY AND CHARGE CORRELATION-FUNCTION IN THE D-P MODEL Reviewed

    A KOBAYASHI, M AZAMI, Y ONO, T MATSUURA, Y KURODA, K MIURA

    PHYSICA C   250 ( 3-4 )   307 - 319   1995.8

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:ELSEVIER SCIENCE BV  

    The properties of the charge fluctuation are investigated in the d-p model with the repulsion U-pd between holes on the nearest-neighbor Cu and O sites and the infinite on-site repulsion U-d at the Cu site. We calculate the charge susceptibility chi(c)(q, i omega(n)) and the charge correlation function S-c(q)=T Sigma(omega n)chi(c)(q, i omega(n)). It is found that S-c(q) has a peak at the Gamma point and a maximum in a ring around the Gamma point. The former is due to T chi(c)(q, 0). Its intensity is proportional to temperature T and strongly enhanced by U-pd. The latter is due to T Sigma(omega n not equal 0)chi(c)(q, i omega(n)) and shows a weak T and U-pd dependence. The intensity of the diffuse X-ray scattering on taking the charge fluctuation into account is also calculated. The result is consistent with the experiments in La2-deltaSrdeltaCuO4.

    DOI: 10.1016/0921-4534(95)00360-6

    Web of Science

    researchmap

  • FINITE-TEMPERATURE CROSSOVER IN THE D-P MODEL Reviewed

    Y ONO, T MATSUURA, Y KURODA

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   64 ( 5 )   1595 - 1615   1995.5

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:PHYSICAL SOC JAPAN  

    We investigate finite temperature properties of the U-d-infinite d-p model in the auxiliary boson representation within the leading order approximation in the 1/N-expansion. We obtain a unified description of the system valid over the whole temperature range divided by the two characteristic energies, the binding energy of the resonance state of the auxiliary boson, omega(0), and the coherence temperature, T-0, of O (omega(0)/10). At T much less than T-0, a new coherent band (in-gap band) appears inside the charge-transfer gap upon carrier doping and behaves as Fermi liquid with large Fermi surface determined by the Luttinger sum rule. The band width is an increasing function of carrier doping rate and of O (omega(0)). At T &gt; omega(0), the chemical potential is below the in-gap band and the doped holes are mostly on the O-2p band forming small Fermi surface, while the Cu-3d holes behave like spin-1/2 localized moments. At T-0 less than or equal to T less than or equal to omega(0), crossover phenomena between the two limiting cases are observed. The in-gap band becomes quasi-coherent and the inverse life-time due to the incoherent scattering increases linearly with T. The observed crossover phenomena show significant contrast to the distinct phase transition obtained in the mean field theory.

    DOI: 10.1143/JPSJ.64.1595

    Web of Science

    researchmap

  • TRANSPORT-PROPERTIES OF THE IN-GAP STATES IN THE D-P MODEL Reviewed

    SAWADA, I, Y ONO, T MATSUURA, Y KURODA

    PHYSICA C-SUPERCONDUCTIVITY AND ITS APPLICATIONS   245 ( 1-2 )   93 - 125   1995.4

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:ELSEVIER SCIENCE BV  

    We develop an approximation procedure to calculate the optical conductivity sigma(omega) and the electronic Raman scattering intensity in the d-p model by including terms of the leading order in the expansion from the large limit of the spin-orbital degeneracy N at T less than or similar to T-0, where the well-defined quasi-particle states called in-gap states emerge inside the charge-transfer gap upon hole doping to the half-filled case. Here, T-0 is the coherence temperature of 0.2 omega(0), where omega(0) is a half of the band width of the in-gap states at T = 0 and is proportional to the doped hole concentration delta at delta less than or similar to 0.1. The in-gap states are shown to contribute to the Drude components in sigma(omega) with an intensity also proportional to delta at delta less than or similar to 0.1, as has been observed in experiments. Both the omega and the T dependence in sigma(omega) are found to be scaled well by omega(0). The generalized Drude analysis (GDA) of sigma(omega) shows that both the optical mass m(opt)(omega) and the optical scattering rate tau(opt)(*)(omega(-1) are only weakly omega dependent in contradiction to the experimental observations, which seems to suggest that the in-gap states at T less than or similar to T-0 do not account for the anomalous optical properties of high-T-c superconductors. We show that the omega dependence of the quasi-particle scattering rate plays a crucial role for determining the omega dependence of the optical mass m(opt)(omega) and comment on the confusion regarding GDA seen among physicists.

    DOI: 10.1016/0921-4534(95)00097-6

    Web of Science

    researchmap

  • NUMERICAL STUDY ON SUPERCONDUCTIVITY IN THE ONE-DIMENSIONAL D-P MODEL Reviewed

    K SANO, Y ONO

    PHYSICA C   242 ( 1-2 )   113 - 120   1995.2

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:ELSEVIER SCIENCE BV  

    Using the numerical diagonalization method and Luttinger liquid theory, we investigate the one-dimensional d-p model, simulating a Cu-O linear chain with strong Coulomb repulsion. In our previous work [Physica C 205 (1993) 170], we have found that the superconducting correlation is dominant in the existence both of a large on-site repulsion at the Cu-site, U-d, and an inter-site repulsion, U-pd, between the nearest-neighbor Cu- and O-sites. In this paper, to clarify the superconducting phase in more detail, we calculate various types of pairing correlation functions. The results indicate that the pairing on O-sites dominates over the pairing on Cu-sites and on the nearest-neighbor Cu- and O-sites. We also investigate the effect of the on-site repulsion at the O-site, U-p, on the pairing correlation and a critical exponent of correlation functions. These results suggest that the superconducting phase promoted by the repulsion U-pd remains against U-p.

    DOI: 10.1016/0921-4534(94)02314-X

    Web of Science

    researchmap

  • PHASE-DIAGRAMS OF THE ELECTRONIC-STATE OF THE ONE-DIMENSIONAL D-P MODEL Reviewed

    K SANO, Y ONO

    PHYSICAL REVIEW B   51 ( 2 )   1175 - 1180   1995.1

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:AMER PHYSICAL SOC  

    DOI: 10.1103/PhysRevB.51.1175

    Web of Science

    researchmap

  • 1/N EXPANSION STUDY OF TRANSPORT PHENOMENA IN THE D-P MODEL Reviewed

    SAWADA, I, Y ONO, T MATSUURA, Y KURODA

    PHYSICA C-SUPERCONDUCTIVITY AND ITS APPLICATIONS   235   2293 - 2294   1994.12

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:ELSEVIER SCIENCE BV  

    We investigate transport phenomena in the normal state of the simplest d-p model using the auxiliary boson technique together with the 1/N expansion method. Analysis of the optical conductivity with the generalized Drude formula shows that omega-dependence of the optical lifetime tau(opt)(omega) is like non-Fermi liquid and that the optical mass m(opt)*(omega) is of order of the band mass m(b) and almost independent of omega and the doped hole concentration delta.

    DOI: 10.1016/0921-4534(94)92368-X

    Web of Science

    researchmap

  • ELECTRONIC-STRUCTURE OF ONE-DIMENSIONAL EXTENDED HUBBARD-MODEL Reviewed

    K SANO, Y ONO

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   63 ( 4 )   1250 - 1253   1994.4

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:PHYSICAL SOC JAPAN  

    We investigated the one-dimensional extended Hubbard model with the on-site interaction U and the nearest-neighbor interaction V by using the numerical diagonalization method. Assuming the Luttinger liquid relations, we obtained the phase diagram of the ground state on the U-V plane. In the weak coupling region, the phase diagram agrees with the result of geology. On the other hand, in the strong coupling region for V much greater than \t\, a novel superconducting phase appears both for positive and negative U. We also investigated the charge gap and the spin gap. The results suggest that the superconducting phase extends over the Tomonaga-Luttinger region (without spin gap) and the Luther-Emery region (with spin gap).

    DOI: 10.1143/JPSJ.63.1250

    Web of Science

    researchmap

  • KONDO INSULATOR AND CHARGE-TRANSFER INSULATOR IN LATTICE ANDERSON MODEL Reviewed

    Y ONO, T MATSUURA, Y KURODA

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   63 ( 4 )   1406 - 1421   1994.4

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:PHYSICAL SOC JAPAN  

    Properties of the heavy-fermion valence-fluctuating compounds leading to insulating ground states (called Kondo insulators) are investigated theoretically by using the U-infinite degenerate lattice Anderson model in the auxiliary boson representation. The model is treated within the approximation including terms of the leading order in the expansion w.r.t. inverse of the spin-orbit degeneracy (1/N-expansion) under the strict local constraints guaranteeing equivalence of the bosonic version to the original U-infinite model. The results are compared with the experimental observations on the possible candidates for Kondo insulators. Differences between Kondo insulators and charge transfer type insulators now paid much attention as the mother systems for the high-T(c) superconductors are briefly discussed on a unified basis within the model described above.

    DOI: 10.1143/JPSJ.63.1406

    Web of Science

    researchmap

  • STRONGLY CORRELATED ELECTRONS IN MIXED-VALENCE CONDUCTORS DCNQI-CU SALTS Reviewed

    Y SUZUMURA, Y ONO

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   62 ( 9 )   3244 - 3256   1993.9

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:PHYSICAL SOC JAPAN  

    Organic conductors, DCNQI-Cu salts, with a mixed valence Cu+4/3 on the average has been studied theoretically by applying the slave-boson method to the strongly correlated systems which consist of pi-electrons of DCNQI molecule and d-electrons of Cu atoms. The ground state is calculated by use of the 1/N(sigma) expansion method which treats the local constraint strictly. It is shown that the electron mass around the Fermi surface is enhanced in the presence of the charge density with the three-fold periodicity.

    DOI: 10.1143/JPSJ.62.3244

    Web of Science

    researchmap

  • CHARGE FLUCTUATION AND SUPERCONDUCTIVITY IN THE ONE-DIMENSIONAL D-P MODEL Reviewed

    K SANO, Y ONO

    PHYSICA C   205 ( 1-2 )   170 - 176   1993.1

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:ELSEVIER SCIENCE BV  

    The one-dimensional two-band Hubbard model, simulating a Cu-O linear chain with infinite intra-site Coulomb repulsion among holes at the Cu-sites, is solved exactly by using the numerical diagonalization method. It is confirmed that inter-site Coulomb repulsion between holes at the nearest-neighbor Cu- and 0-sites enhances the charge fluctuation as well as the superconducting fluctuations, and when it exceeds a certain critical value the system becomes unstable towards the phase separation. By assuming the Luttinger liquid relations to hold in the present system, the critical exponents in the superconducting, CDW and SDW correlation functions are also calculated. The results suggest that in the proximity of the phase boundary towards the phase separation, the superconducting correlation is dominant compared with the CDW and SDW correlations.

    DOI: 10.1016/0921-4534(93)90184-R

    Web of Science

    researchmap

  • CHARGE FLUCTUATION AND SUPERCONDUCTIVITY IN THE D-P MODEL Reviewed

    DS HIRASHIMA, Y ONO, T MATSUURA, Y KURODA

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   61 ( 2 )   649 - 665   1992.2

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:PHYSICAL SOCIETY JAPAN  

    We investigate effects of the repulsive interaction U(pd) between holes on the nearest-neighbor Cu- and O-sites in the d-p model with infinite repulsion on the Cu site using the auxiliary boson technique and the 1/N expansion method. It is found that the condition for a metal-insulator (M-1) transition to occur at the half-filled case is modified. We then investigate the charge susceptibility; it is found that the thermodynamic charge susceptibility is enhanced by U(pd) except for the region around the critical point of the M-1 transition. It is found to diverge at a certain value of U(pd). which implies an instability toward a phase separation. On the basis of these calculations, we obtain phase diagrams, which consist of the metallic, unstable (phase-separating) and insulating phases. Furthermore, we calculate the quasiparticle interaction and find that the charge fluctuation induces attractive interaction comparable in magnitude to the repulsive interaction originating from the on-site repulsion U(d) in both of the s- and d-wave channel; in the immediate vicinity of the instability, the attraction can overcome the repulsion.

    DOI: 10.1143/JPSJ.61.649

    Web of Science

    researchmap

  • Electronic states and charge fluctuation in the CuO-based superconducting materials Reviewed

    T. Matsuura, K. Miura, Y. Ono, D. S. Hirashima

    Electronic Properties and Mechanisms of High-Tc Superconductors   229 - 239   1992

     More details

    Language:English   Publishing type:Research paper (international conference proceedings)   Publisher:Elsevier  

    researchmap

  • Electronic States and Charge Fluctuation on the CuO2-2D Lattice Invited Reviewed

    DS Hirashima, Y Ono, T Matsuura, Y Kuroda, H Jichu

    The Physics and Chemistry of Oxide Superconductors   135 - 137   1992

     More details

    Language:English   Publishing type:Research paper (international conference proceedings)   Publisher:Springer, Berlin, Heidelberg  

    DOI: 10.1007/978-3-642-77154-5_23

    researchmap

  • ON THE 1/N-EXPANSION STUDIES OF INFINITE-U ANDERSON MODELS Reviewed

    Y KURODA, Y ONO, K MIURA, B JIN, H JICHU, DS HIRASHIMA, T MATSUURA

    PROGRESS OF THEORETICAL PHYSICS SUPPLEMENT   108 ( 108 )   173 - 198   1992

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:PROGRESS THEORETICAL PHYSICS PUBLICATION OFFICE  

    The most important results obtained through a series of the present authors' studies on the bosonic versions of the infinite- U impurity- and lattice-Anderson models with use of the rigorous expansion with respect to inverse power of the spin-orbit degeneracy N (1/N-expansion) are reviewed and their physical implications are discussed in comparison with the results obtained in the other 1/N-expansion studies as well as their relating experimental observations.

    DOI: 10.1143/PTPS.108.173

    Web of Science

    researchmap

  • FINITE TEMPERATURE CROSSOVER IN THE ANDERSON LATTICE MODEL Reviewed

    Y ONO, K MIURA, T MATSUURA, Y KURODA

    PHYSICA C   185   1669 - 1670   1991.12

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:ELSEVIER SCIENCE BV  

    The infinite-U Anderson lattice model is studied by using the 1/N-expansion method with taking account of the local electronic correlation rigorously. In order to understand T-dependence of properties of the system properly, another characteristic energy originated from the quasi-particle band structure is found to be introduced in addition to the coherence temperature and the Kondo temperature.

    DOI: 10.1016/0921-4534(91)90961-W

    Web of Science

    researchmap

  • ELECTRONIC STATE AND SUPERCONDUCTIVITY IN THE D-P MODEL Reviewed

    DS HIRASHIMA, Y ONO, T MATSUURA, Y KURODA

    PHYSICA C   185   1513 - 1514   1991.12

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:ELSEVIER SCIENCE BV  

    Electronic state of the d-p hybridization model with infinite repulsion on the Cu site is investigated with the help of the auxilliary boson technique and the 1/N expansion method. In particular, effects of the repulsion U(pd) between the holes on the nearest-neighbor Cu and O sites are clarified; it is shown that the charge fluctuation is enhanced by U(pd). Possible relevance to superconductivity is discussed.

    DOI: 10.1016/0921-4534(91)90883-Z

    Web of Science

    researchmap

  • METAL-INSULATOR-TRANSITION AND CHARGE FLUCTUATION IN THE D-P MODEL Reviewed

    DS HIRASHIMA, Y ONO, K MIURA, T MATSUURA, H JICHU

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   60 ( 7 )   2269 - 2284   1991.7

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:PHYSICAL SOCIETY JAPAN KIKAI-SHINKO BUILDING  

    Electronic states in the d-p model, particularly those around the half-filled case, are investigated with the help of the auxiliary boson method and the 1/N-expansion. The critical value of the charge transfer energy for a metal-insulator transition to occur at the half-filled case is evaluated. The analytic expression for the charge susceptibility is given. Then characteristics of the charge fluctuation around the transition point are clarified; it is found that the charge susceptibility vanishes on the critical point. Furthermore, dependence of the charge susceptibility on the hole number and on the charge transfer energy is studied. Relevance to high temperature superconducting materials is then discussed.

    DOI: 10.1143/JPSJ.60.2269

    Web of Science

    researchmap

  • CHARGE FLUCTUATION IN THE D-P MODEL - EFFECTS OF THE REPULSIVE INTERACTION BETWEEN D-HOLES AND P-HOLES Reviewed

    DS HIRASHIMA, Y ONO, T MATSUURA, Y KURODA

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   60 ( 6 )   1864 - 1868   1991.6

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:PHYSICAL SOCIETY JAPAN  

    We investigate effects of the repulsive interaction U(pd) between holes on the nearest-neighbor Cu- and O-sites in the d-p model, a model suitable to describe the CuO2 plane in high-temperature superconductors. It is found that the condition for a metal-insulator (M-I) transition to occur at the half-filled case is modified. Furthermore, the charge susceptibility is found to be enhanced by U(pd), except for the region around the critical point of the M-I transition; it indeed diverges at a certain value of U(pd). Possible relevance of the enhanced charge susceptibility to the mechanism of the high T(c) superconductivity is discussed.

    DOI: 10.1143/JPSJ.60.1864

    Web of Science

    researchmap

  • Finite Temperature Crossover in the Lattice Anderson Model

    Yoshiaki Ono

    1991.3

  • SPIN-WAVE THEORY OF THE SQUARE-LATTICE HEISENBERG-ANTIFERROMAGNET Reviewed

    T AOKI, Y ONO

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   60 ( 3 )   1142 - 1143   1991.3

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:PHYSICAL SOCIETY JAPAN KIKAI-SHINKO BUILDING  

    DOI: 10.1143/JPSJ.60.1142

    Web of Science

    researchmap

  • ELECTRONIC STATES IN THE CU-OXIDE SUPERCONDUCTORS Reviewed

    T MATSUURA, K MIURA, Y ONO, D HIRASHIMA, Y KURODA

    PROGRESS OF THEORETICAL PHYSICS SUPPLEMENT   106 ( 106 )   51 - 62   1991

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:PROGRESS THEORETICAL PHYSICS PUBLICATION OFFICE  

    The d-p model with the local constraint has been studied. With help of the slave boson and 1/N-expansion the electronic states are investigated. At T &lt; T0 (coherence temperature) a new band (mid-gap state) appears in the CT gap which behaves as the Fermi liquid with the large Fermi surface. Luttinger sum rule is proved. At T0 less-than-or-similar-to T less-than-or-similar-to omega(0) (resonance temperature) the mid-gap state behaves as the marginal Fermi liquid. At T greater-than-or-similar-to omega(0) such renormalized band collapses. These occur as the crossover phenomena in contrast to the phase transition in the mean field approximation. The anomalous physical properties are observed in the temperature region of the marginal Fermi liquid. The system is metallic or insulating at non-doping limit when DELTABAR = DELTA/2t(pd) &lt; 2.37 or DELTABAR &gt; 2.37. For DELTABAR = 2.37, the charge susceptibility becomes zero, which is a characteristic feature of the strongly correlated system. U(pd) changes the critical value of DELTABAR, enhances the charge fluctuation and causes the phase separation. The interactions mediated by the enhanced charge fluctuation may derive the superconductivity of the cuprate compounds.

    DOI: 10.1143/PTP.106.51

    Web of Science

    researchmap

  • Electronic State of the Anderson Lattice over the Whole Temperature Range Reviewed

    Yoshiaki Ōno, Tamifusa Matsuura, Yoshihiro Kuroda

    Journal of the Physical Society of Japan   60 ( 10 )   3475 - 3500   1991

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:The Physical Society of Japan  

    Earlier we proposed a modified version of the Anderson lattice model where the in-tersite coherence effects can be properly included even in the large limit of the spin-orbital degeneracy N and investigated the low temperature Fermi liquid properties rigorously in the limit N→ ∞. In the present study, using the same model as above, we investigate properties over the whole temperature range through explicit numerical calculations for 7V=6. We find that a coherence temperature T0 of order of one tenth of the Kondo temperature TK exists
    at lower temperature T≲T0 the system is in the Fermi liquid state, while at higher temperature T≫ T0 the electrons are scattered incoherently by the Kondo impurities. At intermediate temperature, with increasing T, the hybridization gap appeared in the Fermi liquid state decreases rapidly at T≳ T0, then smoothly turns into the pseudo gap at T⋍ TK, and finally the dense Kondo regime is realized at T. TK. © 1991, THE PHYSICAL SOCIETY OF JAPAN. All rights reserved.

    DOI: 10.1143/JPSJ.60.3475

    Scopus

    researchmap

  • ELECTRONIC STATE OF STRONGLY CORRELATED ELECTRONS Reviewed

    Y ONO, T MATSUURA

    PHYSICA C   159 ( 6 )   875 - 877   1989.8

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:ELSEVIER SCIENCE BV  

    DOI: 10.1016/0921-4534(89)90162-7

    Web of Science

    researchmap

  • CRITICAL-STUDY OF STRONGLY CORRELATED SYSTEMS - A UNIFIED DESCRIPTION OF THE INCOHERENT AND COHERENT REGIMES Reviewed

    Y ONO, T MATSUURA, Y KURODA

    PHYSICA C   159 ( 6 )   878 - 888   1989.8

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:ELSEVIER SCIENCE BV  

    DOI: 10.1016/0921-4534(89)90163-9

    Web of Science

    researchmap

  • QUASI-PARTICLES IN THE DEGENERATE LATTICE ANDERSON MODEL Invited Reviewed

    Y KURODA, Y ONO, T MATSUURA, H JICHU

    STRONG CORRELATION AND SUPERCONDUCTIVITY   89   167 - 175   1989

     More details

    Language:English   Publishing type:Research paper (international conference proceedings)   Publisher:SPRINGER-VERLAG BERLIN  

    DOI: 10.1007/978-3-642-83836-1_17

    Web of Science

    researchmap

▶ display all

MISC

  • 7aBH-9 A theory for orbital order in iron-based superconductors due to d-p orbital correlation

    Yamada Takemi, Ono Yoshiaki

    Meeting abstracts of the Physical Society of Japan   69 ( 2 )   325 - 325   2014.8

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 9aPS-58 The effect of AB intersite d-p orbital correlation in A15 compound (A_3B)

    Ogata K., Yamada T., Ishizuka J., Ono Y.

    Meeting abstracts of the Physical Society of Japan   69 ( 2 )   416 - 416   2014.8

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 30aCG-12 Orbital selective Mott transition and heavy-fermion state in the iron-based superconductors by using the dynamical mean-field theory

    Yamada Takemi, Ishizuka Jun, Ono Yoshiaki

    Meeting abstracts of the Physical Society of Japan   69 ( 1 )   670 - 670   2014.3

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 30aCG-5 DMFT+Eliashberg Study for Iron-based Superconductors

    Ishizuka J., Yamada T., Yanagi Y., Ono Y.

    Meeting abstracts of the Physical Society of Japan   69 ( 1 )   668 - 668   2014.3

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 30aCG-10 d-p orbital correlation effects on the elastic softening and pairing mechanism in the iron-based superconductors

    Yamada Takemi, Ishizuka Jun, Ono Yoshiaki

    Meeting abstracts of the Physical Society of Japan   69 ( 1 )   670 - 670   2014.3

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • Magnetic and orbital fluctuations and superconductivity in the iron-based superconductors based on the dynamical mean-field theory III

    Ishizuka J., Yamada T., Yanagi Y., Ono Y.

    Meeting abstracts of the Physical Society of Japan   68 ( 2 )   523 - 523   2013.8

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • Orbital selective Mott transition in the 5-orbital Hubbard model for the iron-based superconductivitors

    Yamada Takemi, Ono Yoshiaki

    Meeting abstracts of the Physical Society of Japan   68 ( 2 )   439 - 439   2013.8

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • Anomalous flux quantization in the attractive 1D Hubbard ring and Hubbard ladder with imbalanced spin populations

    Sano K., Ono Y.

    Meeting abstracts of the Physical Society of Japan   68 ( 2 )   124 - 124   2013.8

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • Electronic structure of A15 compounds based on multi-orbital effective model

    Ogata K., Yamada T., Ishizuka J., Ono Y.

    Meeting abstracts of the Physical Society of Japan   68 ( 2 )   522 - 522   2013.8

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 26pXX-4 Magnetic and orbital order and band renormalization effect of iron-based superconductors based on dynamic mean-field theory

    Kasai T., Yamada T., Ono Y.

    Meeting abstracts of the Physical Society of Japan   68 ( 1 )   587 - 587   2013.3

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 26pXX-5 Magnetic and orbital fluctuations and superconductivity of the iron-based superconductor II

    Ishizuka J., Yanagi Y., Yamada T., Kasai T., Ono Y.

    Meeting abstracts of the Physical Society of Japan   68 ( 1 )   588 - 588   2013.3

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 20aAL-9 Anomalous flux quantization in the attractive ID Hubbard ring with imbalanced spin populations II

    Sano K., Ono Y.

    Meeting abstracts of the Physical Society of Japan   67 ( 2 )   167 - 167   2012.8

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 20pPSB-4 Magnetic order and orbital order of iron-based superconductivity by dynamical mean field theory

    Kasai T., Yamada T., Ono Y.

    Meeting abstracts of the Physical Society of Japan   67 ( 2 )   557 - 557   2012.8

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 18pFF-11 Material dependence of spin and orbital fluctuations and its relationship with T_c in iron-based superconductors III

    Uemori Yukito, Yanagi Yuki, Ono Yoshiaki

    Meeting abstracts of the Physical Society of Japan   67 ( 2 )   459 - 459   2012.8

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 20aFH-3 Heavy fermion state and its superconductivity in the multi-orbital Anderson lattice model coupled to the Jahn-Teller phonons

    Yamada Takemi, Ono Yoshiaki, Mitsumoto Keisuke

    Meeting abstracts of the Physical Society of Japan   67 ( 2 )   499 - 499   2012.8

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 18pFF-12 Dynamical mean-field theory for the pairing interaction of iron-based superconductivity

    Yamada Takemi, Ono Yoshiaki

    Meeting abstracts of the Physical Society of Japan   67 ( 2 )   459 - 459   2012.8

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 20pPSB-1 Magnetic and orbital fluctuations and superconductivity of the iron-based superconductor by dynamical mean-field theory

    Ishizuka J., Yanagi Y., Yamada T., Ono Y.

    Meeting abstracts of the Physical Society of Japan   67 ( 2 )   557 - 557   2012.8

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 27aYA-4 Strong correlation effect and magnetic- and orbital-fluctuation in the 2-orbital Hubbard-Holstein model by using the dynamical mean-field theory

    Yamada Takemi, Ono Yoshiaki, Mitsumoto Keisuke

    Meeting abstracts of the Physical Society of Japan   67 ( 1 )   678 - 678   2012.3

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 27aYA-5 Self-consistent fluctuation theory on the electronic states in iron pnictides II

    Yanagi Yuki, Ono Yoshiaki

    Meeting abstracts of the Physical Society of Japan   67 ( 1 )   678 - 678   2012.3

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 25aPS-69 Material dependence of spin and orbital fluctuations and its relationship with T_c in iron-based superconductors II

    Uemori Yukito, Yanagi Yuki, Ono Yoshiaki

    Meeting abstracts of the Physical Society of Japan   67 ( 1 )   609 - 609   2012.3

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 25aPS-71 Dynamical mean-field theory for iron-based superconductor on minimal model II

    Kasai T., Yanagi Y., Yamada T., Ono Y.

    Meeting abstracts of the Physical Society of Japan   67 ( 1 )   609 - 609   2012.3

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 24aBA-10 Anomalous flux quantization in the attractive 1D Hubbard ring with imbalanced spin populations

    Sano K., Ono Y.

    Meeting abstracts of the Physical Society of Japan   67 ( 1 )   181 - 181   2012.3

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 25aPS-72 Orbital and magnetic ordered states of 2-orbital Hubbard model by dynamical mean-field study III

    Hayashi K., Yamada T., Yanagi Y., Ono Y.

    Meeting abstracts of the Physical Society of Japan   67 ( 1 )   609 - 609   2012.3

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • Mechanism of iron-based superconductivity

    Yoshiaki Ono

    Parity   27 ( 1 )   30 - 32   2011.12

     More details

    Language:Japanese   Publishing type:Article, review, commentary, editorial, etc. (trade magazine, newspaper, online media)   Publisher:Maruzen Publishing  

    researchmap

  • 22aGQ-8 Extension and correlation effects of the charge states on silicon vacancy

    Yamada Takemi, Yamakawa Youichi, Ono Yoshiaki

    Meeting abstracts of the Physical Society of Japan   66 ( 2 )   981 - 981   2011.8

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 22pPSA-1 Material dependence of spin and orbital fluctuations and its relationship with T_c in iron-based superconductors

    Uemori yukito, Yanagi Yuki, Ono Yoshiaki

    Meeting abstracts of the Physical Society of Japan   66 ( 2 )   555 - 555   2011.8

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 22pPSA-4 Dynamical mean-field theory for iron-based superconductor on minimal model

    Kasai T., Yanagi Y., Yamada T., Ono Y.

    Meeting abstracts of the Physical Society of Japan   66 ( 2 )   555 - 555   2011.8

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 22pPSA-3 Self-consistent fluctuation theory on the electronic states in iron pnictides

    Yanagi Yuki, Ono Yoshiaki

    Meeting abstracts of the Physical Society of Japan   66 ( 2 )   555 - 555   2011.8

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 22pPSA-2 Orbital and magnetic ordered states of 2-orbital Hubbard model by dynamical mean-field study II

    Hayashi K., yamada T., yanagi Y., Ono Y.

    Meeting abstracts of the Physical Society of Japan   66 ( 2 )   555 - 555   2011.8

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 25pPSB-2 Orbital and magnetic ordered states of 2-orbital Hubbard model by dynamical mean-field study

    Hayashi K., Yamada T., Fuse T., Yamakawa Y., Yanagi Y., Ono Y.

    Meeting abstracts of the Physical Society of Japan   66 ( 1 )   565 - 565   2011.3

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 25aPS-137 Dynamical mean-field theory for heavy fermion state with crystal electric field

    Yamada Takemi, Ono Yoshiaki

    Meeting abstracts of the Physical Society of Japan   66 ( 1 )   546 - 546   2011.3

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 25pPSB-4 Electron Correlations and Orbital Excitations in Resonant Inelastic X-Ray Scattering from Iron-Arsenide Superconductor

    Nomura T., Yamakawa Y., Yanagi Y., Ono Y.

    Meeting abstracts of the Physical Society of Japan   66 ( 1 )   565 - 565   2011.3

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 25pEE-11 The theory of antiferromagnetic and ferro-orbital ordered states and the structural transition for iron-based superconductors

    Adachi Naoko, Yamakawa Youichi, Yanagi Yuki, Ono Yoshiaki

    Meeting abstracts of the Physical Society of Japan   66 ( 1 )   558 - 558   2011.3

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 25pEE-3 s_<++>-wave superconductivity due to the orbital-lattice coupling inthe d-p model for iron pnictides

    Yanagi Yuki, Yamakawa Youichi, Adachi Naoko, Ono Yoshiaki

    Meeting abstracts of the Physical Society of Japan   66 ( 1 )   556 - 556   2011.3

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 鉄系超伝導体における軌道の秩序と揺らぎ(鉄系高温超伝導の物理,研究会報告)

    大野 義章, 安立 奈緒子, 柳 有起, 山川 洋一

    物性研究   96 ( 5 )   538 - 538   2011

     More details

    Language:Japanese   Publisher:物性研究刊行会  

    CiNii Article

    CiNii Books

    researchmap

    Other Link: http://hdl.handle.net/2433/169601

  • 鉄系超伝導体のd-p模型における軌道-格子結合効果(鉄系高温超伝導の物理,研究会報告)

    柳 有起, 山川 洋一, 安立 奈緒子, 大野 義章

    物性研究   96 ( 5 )   561 - 561   2011

     More details

    Language:Japanese   Publisher:物性研究刊行会  

    CiNii Article

    CiNii Books

    researchmap

    Other Link: http://hdl.handle.net/2433/169578

  • 26aWZ-13 Strongly correlated and coupled quantum state and spin-orbit interaction in a silicon vacancy

    Yamakawa Youichi, Yamada Takemi, Ono Yoshiaki

    Meeting abstracts of the Physical Society of Japan   65 ( 2 )   928 - 928   2010.8

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 23aPS-41 Dynamical mean-field study of the 2-orbital Hubbard model for iron-based superconductors

    Hayashi K., Yamada T., Fuse T., Yamakawa Y., Yanagi Y., Ono Y.

    Meeting abstracts of the Physical Society of Japan   65 ( 2 )   469 - 469   2010.8

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 25aWG-4 Effects of the intersite repulsion between 3d and 4p electrons U_<pd> on the d-p model for the iron-based superconductors

    Yanagi Yuki, Yamakawa Youichi, Adachi Naoko, Ono Yoshiaki

    Meeting abstracts of the Physical Society of Japan   65 ( 2 )   580 - 580   2010.8

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 25aWG-3 Magnetic, orbital and charge ordered states and the effect of the Electron-Lattice Coupling in the two-dimensional 16-band d-p model

    Adachi Naoko, Yamakawa Youichi, Yanagi Yuki, Ono Yoshiaki

    Meeting abstracts of the Physical Society of Japan   65 ( 2 )   580 - 580   2010.8

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 23pWJ-8 Electronic states of Kondo semiconductor system using the dynamical mean-field theory

    Yamada Takemi, Ono Yoshiaki

    Meeting abstracts of the Physical Society of Japan   65 ( 2 )   506 - 506   2010.8

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 20pHT-6 Electron correlation and nonadiabatic effects in a silicon vacancy and elastic softening III

    Yamakawa Youichi, Yamada Takemi, Ono Yoshiaki

    Meeting abstracts of the Physical Society of Japan   65 ( 1 )   979 - 979   2010.3

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 20pPSB-2 Magnetic, orbital and charge ordered states in the d-p model for iron-based superconductors

    Adachi Naoko, Yamakawa Youichi, Yanagi Yuki, Ono Yoshiaki

    Meeting abstracts of the Physical Society of Japan   65 ( 1 )   577 - 577   2010.3

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 20pPSB-1 Phase diagram of the d-p model for iron-based superconductors including the s_±-wave and the s_<++>-wave superconductivity

    Yanagi Yuki, Yamakawa Youichi, Adachi Naoko, Ono Yoshiaki

    Meeting abstracts of the Physical Society of Japan   65 ( 1 )   577 - 577   2010.3

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 26aPS-90 Theoretical Stud of Resonant Inelastic X-Ray Scattering in Iron Pnictides

    Nomura T., Yamakawa Y., Yanagi Y., Ono Y.

    Meeting abstracts of the Physical Society of Japan   64 ( 2 )   497 - 497   2009.8

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 26pRL-9 Mechanism of superconductivity in oxypnictide superconductors based on the two-dimensional 16-band d-p model II

    Yanagi Yuki, Yamakawa Youichi, Ono Yoshiaki

    Meeting abstracts of the Physical Society of Japan   64 ( 2 )   519 - 519   2009.8

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 25pYK-11 Electron correlation and nonadiabatic effects in a silicon vacancy and elastic softening II

    Yamakawa Youichi, Yamada Takemi, Ono Yoshiaki

    Meeting abstracts of the Physical Society of Japan   64 ( 2 )   863 - 863   2009.8

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 25pYK-12 Effect of the spin-orbit interaction and the electron phonon coupling on the electronic state in a silicon vacancy

    Yamada Takemi, Yamakawa Youichi, Ono Yoshiaki

    Meeting abstracts of the Physical Society of Japan   64 ( 2 )   864 - 864   2009.8

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 26aPS-66 Effects of ferromagnetic fluctuations on the electronic states and the transport properties in Na_xCoO_2

    Yanagi Yuki, Ono Yoshiaki

    Meeting abstracts of the Physical Society of Japan   64 ( 2 )   493 - 493   2009.8

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 28aTC-9 Mechanism of superconductivity in oxypnictide superconductors based on the two-dimensional 16-band d-p model

    Yanagi Yuki, Yamakawa Youichi, Ono Yoshiaki

    Meeting abstracts of the Physical Society of Japan   64 ( 1 )   586 - 586   2009.3

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 29pTL-1 New Structural Transition Mechanism of Li_2RuO_3 with Pseudo Honeycomb Structure

    Miura Yoko, Sato Masatoshi, Yamakawa Youichi, Habaguchi Tatsuro, Ono Yoshiaki

    Meeting abstracts of the Physical Society of Japan   64 ( 1 )   636 - 636   2009.3

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 27aRB-9 Effect of the spin-orbit interaction on the electronic state in a silicon vacancy

    Yamada Takemi, Yamakawa Youichi, Ono Yoshiaki

    Meeting abstracts of the Physical Society of Japan   64 ( 1 )   932 - 932   2009.3

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 27pPSB-64 Electronic structure of diluted magnetic semiconductor and strong correlation effect

    Suzuki Ryo, Yamakawa Yoichi, Ono Yoshiaki

    Meeting abstracts of the Physical Society of Japan   64 ( 1 )   695 - 695   2009.3

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 28aTC-8 Effective d-p model and electronic state of LaFeAsO

    Yamakawa Youichi, Yanagi Yuki, Ono Yoshiaki

    Meeting abstracts of the Physical Society of Japan   64 ( 1 )   586 - 586   2009.3

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 22pQB-3 Quantum state and rattling in Off-Center type anharmonic potential

    Fuse T., Yamakawa Y., Ono Y.

    Meeting abstracts of the Physical Society of Japan   63 ( 2 )   550 - 550   2008.8

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 20pQF-15 Electron correlation and nonadiabatic effects in a silicon vacancy and elastic softening

    Yamakawa Youichi, Yamada Takemi, Ono Yoshiaki

    Meeting abstracts of the Physical Society of Japan   63 ( 2 )   458 - 458   2008.8

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 20pPSA-18 Extension of the charge state and elastic softening in a silicon vacancy

    Meeting abstracts of the Physical Society of Japan   63 ( 2 )   463 - 463   2008.8

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 21aYA-6 Superconductivity in the Two-Orbital Hubbard Model

    Sano K., Ono Y.

    Meeting abstracts of the Physical Society of Japan   63 ( 2 )   492 - 492   2008.8

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 21aYA-7 Electronic states in oxypnictide superconductors based on the two-dimensional 16-band d-p model

    Yanagi Yuki, Yamakawa Youichi, Ono Yoshiaki

    Meeting abstracts of the Physical Society of Japan   63 ( 2 )   492 - 492   2008.8

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 21aQE-11 Field dependence of successive transition in the two dimensional triangular lattice d-p model

    Yamakawa Youichi, Ono Yoshiaki

    Meeting abstracts of the Physical Society of Japan   63 ( 2 )   487 - 487   2008.8

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 21pRB-3 Extension of the charge state and correlation effects in a silicon vacancy

    Ono Yoshiaki, Yamakawa Youichi, Yamada Takemi

    Meeting abstracts of the Physical Society of Japan   63 ( 2 )   875 - 875   2008.8

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 21aPS-3 Effects of enharmonic phonons on the superconductivity in the Holstein model

    Kawamura Tomoki, Mitsumoto Keisuke, Ono Yoshiaki

    Meeting abstracts of the Physical Society of Japan   63 ( 2 )   494 - 494   2008.8

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 24pYF-5 Local electronic state in a silicon vacancy by using the Green's function

    Meeting abstracts of the Physical Society of Japan   63 ( 1 )   937 - 937   2008.2

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 24aPS-44 Electronic states in Na_xCoO_2 based on the three orbital Hubbard model

    Yanagi Yuki, Ono Yoshiaki

    Meeting abstracts of the Physical Society of Japan   63 ( 1 )   581 - 581   2008.2

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 25pWR-9 Anharmonic phonon effects in the Holstein model

    Kawamura Tomoki, Mitsumoto Keisuke, Ono Yoshiaki

    Meeting abstracts of the Physical Society of Japan   63 ( 1 )   625 - 625   2008.2

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 24pYF-4 Quantum state in a silicon vacancy with strong correlation and strong coupling III

    Yamakawa Youichi, Mitsumoto Keisuke, Ono Yoshiaki

    Meeting abstracts of the Physical Society of Japan   63 ( 1 )   936 - 936   2008.2

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 21aWF-8 Spin-gap of double chain model

    Sano K., Ono Y.

    Meeting abstracts of the Physical Society of Japan   62 ( 2 )   508 - 508   2007.8

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 21pWF-10 Magnetic, charge and orbital order in the two dimensional triangular lattice d-p model

    Yamakawa Youichi, Ono Yoshiaki

    Meeting abstracts of the Physical Society of Japan   62 ( 2 )   551 - 551   2007.8

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 21pWF-9 Effect of ferromagnetic spin fluctuations on electronic states in Na_xCoO_2 II

    Yanagi Yuki, Ono Yoshiaki

    Meeting abstracts of the Physical Society of Japan   62 ( 2 )   551 - 551   2007.8

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 22pTD-12 Electronic states in the silicon vacancy

    Ono Yoshiaki, Yamakawa Youichi, Yamada Takemi

    Meeting abstracts of the Physical Society of Japan   62 ( 2 )   994 - 994   2007.8

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 21pPSB-2 Anharmonic phonon effects in the periodic Anderson-Holstein model

    Kawamura Tomoki, Mitsumoto Keisuke, Ono Yoshiaki

    Meeting abstracts of the Physical Society of Japan   62 ( 2 )   573 - 573   2007.8

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 23pWE-5 Dynamical mean-field study of electronic states in the multi-orbital Anderson lattice model II

    Mitsumoto Keisuke, Ono Yoshiaki

    Meeting abstracts of the Physical Society of Japan   62 ( 2 )   626 - 626   2007.8

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 21aPS-19 Local electronic state and its magnetic field dependence in a silicon vacancy

    Yamada Takemi, Yamakawa Youichi, Ono Yoshiaki

    Meeting abstracts of the Physical Society of Japan   62 ( 2 )   522 - 522   2007.8

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 18pPSB-50 DMFT study of valence fluctuations and electronic states in the periodic Anderson model

    Fuse T., Mitsumoto K., Ono Y.

    Meeting abstracts of the Physical Society of Japan   62 ( 1 )   539 - 539   2007.2

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 19aXE-5 Effect of ferromagnetic spin fluctuations on electronic states in Na_xCoO_2

    Yanagi Yuki, Ono Yoshiaki

    Meeting abstracts of the Physical Society of Japan   62 ( 1 )   555 - 555   2007.2

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 19pXE-5 Dynamical mean-field study of electronic states in the multi-orbital Anderson lattice model

    Mitsumoto Keisuke, Ono Yoshiaki

    Meeting abstracts of the Physical Society of Japan   62 ( 1 )   601 - 601   2007.2

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 19aXE-4 Magnetic and charge ordered states in the two dimensional triangular lattice d-p model

    Yamakawa Youichi, Ono Yoshiaki

    Meeting abstracts of the Physical Society of Japan   62 ( 1 )   554 - 554   2007.2

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 19aPS-20 Quantum state in a silicon vacancy with strong correlation and strong coupling II

    Yamakawa Youichi, Mitsumoto Keisuke, Ono Yoshiaki

    Meeting abstracts of the Physical Society of Japan   62 ( 1 )   560 - 560   2007.2

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 24aPS-97 The electronic state and superconductivity in B-doped diamond by using the dynamical mean-field theory

    Mitsumoto Keisuke, Ono Yoshiaki

    Meeting abstracts of the Physical Society of Japan   61 ( 2 )   463 - 463   2006.8

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 23pPSB-48 Coupling between rattling and conduction electron in filled skutterudites

    Fuse T., Mitsumoto K., Yamakawa Y., Ono Y.

    Meeting abstracts of the Physical Society of Japan   61 ( 2 )   430 - 430   2006.8

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 23aZG-1 Antiferromagnetism and double transitions in Na_<0.5>CoO_2 based on the two dimensional triangular lattice d-p model

    Yamakawa Youichi, Ono Yoshiaki

    Meeting abstracts of the Physical Society of Japan   61 ( 2 )   380 - 380   2006.8

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 24aPS-33 s-wave superconductivity driven by pair transfer in Na_xCoO_2・yH_2O

    Yanagi Yuki, Ono Yoshiaki

    Meeting abstracts of the Physical Society of Japan   61 ( 2 )   447 - 447   2006.8

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 23aZG-12 Quantum state in a silicon vacancy with strong coupling and strong correlation

    Yamakawa Youichi, Mitsumoto Keisuke, Ono Yoshiaki

    Meeting abstracts of the Physical Society of Japan   61 ( 2 )   383 - 383   2006.8

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 24pZG-6 Superconductivity of double chain t-J model simulating Pr_2Ba_4Cu_7O_<15-δ>

    Sano K., Ono Y.

    Meeting abstracts of the Physical Society of Japan   61 ( 2 )   468 - 468   2006.8

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 28aTC-1 Electronic state in B-doped diamond using the dynamical mean-field theory

    Mitsumoto Keisuke, Ono Yoshiaki

    Meeting abstracts of the Physical Society of Japan   61 ( 1 )   567 - 567   2006.3

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 20aPS-9 Electronic state of layered cobalt oxides : A slave boson approach

    Watanabe Naohiro, Mitumoto Keisuke, Ono Yoshiaki

    Meeting abstracts of the Physical Society of Japan   60 ( 2 )   430 - 430   2005.8

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 22pPSA-75 Strong coupling between local electronic state and dynamical Jahn-Teller distortion at a vacancy in the semiconductors

    Yamakawa Youichi, Mitsumoto Keisuke, Ono Yoshiaki

    Meeting abstracts of the Physical Society of Japan   60 ( 2 )   557 - 557   2005.8

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 20pYJ-7 Rattling and heavy-fermions in the electron-phonon systems with second-order electron-phonon coupling and an anharmonic term

    Mitsumoto Keisuke, Ono Yoshiaki

    Meeting abstracts of the Physical Society of Japan   60 ( 2 )   462 - 462   2005.8

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 22pXL-5 Charge gap of the one-dimensional U-V model

    Sano K., Ono Y., Takano K., Matsuura T.

    Meeting abstracts of the Physical Society of Japan   60 ( 2 )   214 - 214   2005.8

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 20aPS-10 Effect of coupling between the rattling and acoustic phonons in the strongly coupled electron-phonon system

    Mitsumoto Keisuke, Ono Yoshiaki

    Meeting abstracts of the Physical Society of Japan   60 ( 2 )   430 - 430   2005.8

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 24aWM-12 Heavy fermion state in the f^2 periodic Andeison model

    Ono Yoshiaki, Mitsumoto Keisuke

    Meeting abstracts of the Physical Society of Japan   60 ( 1 )   493 - 493   2005.3

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 26pWM-5 Heavy-electron state and superconductivity in the periodic Andcrson-Holstcin model

    Mitsumoto Keisuke, Ono Yoshiaki

    Meeting abstracts of the Physical Society of Japan   60 ( 1 )   588 - 588   2005.3

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 14aWD-7 Heavy-electrons and double-well potential in the periodic Holstein-Anderson model

    Mitsumoto Keisuke, Ono Yoshiaki

    Meeting abstracts of the Physical Society of Japan   59 ( 2 )   527 - 527   2004.8

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 13aWD-3 Superconductivity in the d-p double chain model II

    Sano Kazuhiro, Ono Yoshiaki

    Meeting abstracts of the Physical Society of Japan   59 ( 2 )   458 - 458   2004.8

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 27pXA-12 Heavy-electron state of the periodic Anderson model coupled with localized phonons

    Mitsumoto Keisuke, Ono Yoshiaki

    Meeting abstracts of the Physical Society of Japan   59 ( 1 )   527 - 527   2004.3

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 27aXA-2 Superconductivity in the d-p double chain model

    Sano K, Ono Y

    Meeting abstracts of the Physical Society of Japan   59 ( 1 )   508 - 508   2004.3

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • Ferromagnetism and Superconductivity in the 1D multi-orbital Hubbard Model

    Sano K., Ono Y.

    Meeting abstracts of the Physical Society of Japan   58 ( 2 )   491 - 491   2003.8

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • Plaquette State for Disordered State in Two-Dimensional J_1-J_2 Model

    Takano Kenichi, Kito Yoshiya, Ono Yoshiaki, Sano Kazuhiro

    Meeting abstracts of the Physical Society of Japan   58 ( 2 )   216 - 216   2003.8

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • Effective model for the One-Dimensional d-d Model

    Sano K., Ono Y.

    Meeting abstracts of the Physical Society of Japan   58 ( 1 )   541 - 541   2003.3

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 軌道自由度を持つ一次元ハバードモデルの電子状態(2002年度基研研究会「軌道自由度を持つ強相関電子系の理論の進展」,研究会報告)

    佐野 和博, 大野 義章

    物性研究   79 ( 6 )   1019 - 1020   2003

     More details

    Language:Japanese   Publisher:物性研究刊行会  

    CiNii Article

    CiNii Books

    researchmap

    Other Link: http://hdl.handle.net/2433/97453

  • Effective model for the One-Dimensional d-d Model II

    Sano K, Ono Y

    Meeting abstracts of the Physical Society of Japan   57 ( 2 )   501 - 501   2002.8

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 27pYH-11 Effective model for the One-Dimensional d-d Model

    Sano K., Ono Y.

    Meeting abstracts of the Physical Society of Japan   57 ( 1 )   595 - 595   2002.3

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • Electronic State of the One-Dimensional U-V Model II

    Sano K., Ono Y.

    Meeting abstracts of the Physical Society of Japan   56 ( 2 )   505 - 505   2001.9

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • Ferromagnetism in a two-band Hubbard model in infinite dimensions

    Ono Yoshiaki, Sano Kazuhiro

    Meeting abstracts of the Physical Society of Japan   56 ( 2 )   467 - 467   2001.9

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • Study of 2 Dimensional J_1-J_2 Model by the Nonlinear σ Model Method

    Takano Ken'ichi, Kito Yoshiya, Oho Yoshiaki, Sano Kazuhiro

    Meeting abstracts of the Physical Society of Japan   56 ( 1 )   243 - 243   2001.3

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • Ferro-, Antiferro- and Metamagnetism in the two-band Hubbard Model

    Ono Y., Sano K.

    Meeting abstracts of the Physical Society of Japan   55 ( 2 )   427 - 427   2000.9

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • Electronic State of the One-Dimensional U-V Model : Analysis of Renormalization group and Numerical diagonalization Method

    Sano K., Ono Y.

    Meeting abstracts of the Physical Society of Japan   55 ( 2 )   550 - 550   2000.9

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • フラストレートした2次元量子スピン系の非線形シグマモデルによる研究(基礎物理学研究所短期研究会「量子効果が顕著な役割を果たす磁性現象の新展開」,研究会報告)

    紀藤 吉哉, 高野 健一, 大野 義章, 佐野 和博

    物性研究   72 ( 6 )   802 - 804   1999

     More details

    Language:Japanese   Publisher:物性研究刊行会  

    CiNii Article

    CiNii Books

    researchmap

    Other Link: http://dl.ndl.go.jp/info:ndljp/pid/10939278

  • Effective interactions of the one-dimensional d-p model based on the Luttinger liqud theory

    SANO K., ONO Y.

    Meeting abstracts of the Physical Society of Japan   53 ( 2 )   718 - 718   1998.9

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • The phase diagram of CaV_4O_9 by means of Non linear σ model

    KITO Y., ONO Y., SANA K., TAKANO K.

    Meeting abstracts of the Physical Society of Japan   53 ( 1 )   636 - 636   1998.3

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 6a-T-11 Electronic structure of the one-dimensional d-p model with p-p transfer

    Sano K., Ono Y.

    Meeting abstracts of the Physical Society of Japan   52 ( 2 )   625 - 625   1997.9

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 5a-T-13 The phase diagram of CaV_4O_9 by means of Non linear σ model

    Kito Y., Ono Y., Sano K., Takano K.

    Meeting abstracts of the Physical Society of Japan   52 ( 2 )   601 - 601   1997.9

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • Phase diagram of the one-dimensional d-p model

    Sano K., Ono Y.

    Abstracts of the meeting of the Physical Society of Japan. Sectional meeting   1996 ( 3 )   382 - 382   1996.9

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 2a-YD-4 Phase diagram of the one-dimensional d-p model II

    Sano K, O~~-no Y

    Abstracts of the meeting of the Physical Society of Japan. Sectional meeting   1994 ( 3 )   210 - 210   1994.8

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 30a-J-1 Phase diagram of the one-dimensional d-p model

    Sano K., Ono Y.

    Abstracts of the meeting of the Physical Society of Japan. Annual meeting   48 ( 3 )   254 - 254   1993.3

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 26a-R-8 Phase separation and superconductivity in the one-dimensional d-p model

    Sano K, O^^^no Y

    1992 ( 3 )   296 - 296   1992.9

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 27p-PS-12 Metal-Insulator Transition and Charge Fluctuation in the d-p Model

    Jichu H., Hirashima D., Ono Y., Miura K., Matsuura T.

    1991 ( 3 )   336 - 336   1991.3

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

  • 2a-Q-13 Spin-Wave Theory of the Square-Lattice Heisenberg Antiferromagnet

    Aoki T., Ono.Y.

    1990 ( 3 )   420 - 420   1990.10

     More details

    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

    CiNii Article

    CiNii Books

    researchmap

▶ display all

Presentations

  • シリコン原子空孔における電荷状態の拡がりと相関効果

    山田武見, 山川洋一, 大野義章

    日本物理学会 2011年秋季大会  2011.9 

     More details

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:富山大学  

    researchmap

  • 動的平均場による2軌道ハバード模型の磁気秩序と軌道秩序II

    林健太, 山田武見, 柳有起, 大野義章

    日本物理学会 2011年秋季大会  2011.9 

     More details

    Language:Japanese   Presentation type:Poster presentation  

    Venue:富山大学  

    researchmap

  • 鉄系超伝導体の磁気・軌道秩序に対する電子相関効果

    大野義章, 柳有起, 山田武見, 林健太, 笠井貴文

    日本物理学会 2011年秋季大会  2011.9 

     More details

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:富山大学  

    researchmap

  • 鉄系超伝導体のミニマル・モデルに対する動的平均場理論

    笠井貴文, 柳有起, 山田武見, 柳有起, 大野義章

    日本物理学会 2011年秋季大会  2011.9 

     More details

    Language:Japanese   Presentation type:Poster presentation  

    Venue:富山大学  

    researchmap

  • 鉄系超伝導体の磁気・軌道ゆらぎの物質依存性とTcとの相関

    柳有起, 植森裕紀人, 大野義章

    日本物理学会 2011年秋季大会  2011.9 

     More details

    Language:Japanese   Presentation type:Poster presentation  

    Venue:富山大学  

    researchmap

  • 自己無憧着揺らぎ理論による鉄系超伝導体の電子状態

    柳有起, 大野義章

    日本物理学会 2011年秋季大会  2011.9 

     More details

    Language:Japanese   Presentation type:Poster presentation  

    Venue:富山大学  

    researchmap

  • 動的平均場理論による近藤半導体の電子状態II

    山田武見, 大野義章

    日本物理学会 2011年秋季大会  2011.9 

     More details

    Language:Japanese   Presentation type:Poster presentation  

    Venue:富山大学  

    researchmap

  • Bipolaronic Transition and Heavy Fermions in the Anharmonic Holstein Model International conference

    Takahiro Fuse, Yoshiaki Ono

    Strongly Correlated Electron Systems 2011  2011.8 

     More details

    Language:English   Presentation type:Poster presentation  

    Venue:Cambridge, UK  

    researchmap

  • S++-wave Superconductivity near the Ferro-orbital QCP in Iron Pnictides International conference

    Yoshiaki Ono, Yuki Yanagi, Naoko Adachi, Kenta Hayashi, Youichi Yamakawa

    The 26th International Conference on Low Temperature Physics  2011.8 

     More details

    Language:English   Presentation type:Poster presentation  

    Venue:Beijing, China  

    researchmap

  • Orbital order and its fluctuation in iron pnictide superconductors International conference

    Yoshiaki Ono, Yuki Yanagi, Naoko Adachi, Youichi Yamakawa

    Search for new physics in transition metal compounds by spectroscopies  2011.7 

     More details

    Language:English   Presentation type:Oral presentation (invited, special)  

    Venue:Tokyo, Japan  

    researchmap

  • シリコン原子空孔における強相関・強結合量子状態とスピン軌道相互作用の効果II

    山川洋一, 山田武見, 大野義章

    日本物理学会 第66回年次大会  2011.3 

     More details

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:新潟大学  

    researchmap

  • 鉄系超伝導体の反強磁性・強軌道秩序と構造転移の理論

    安立奈緒子, 山川洋一, 柳有起, 大野義章

    日本物理学会 第66回年次大会  2011.3 

     More details

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:新潟大学  

    researchmap

  • 鉄砒素超伝導体の共鳴非弾性X線散乱における電子相関の効果と軌道励起

    野村拓司, 山川洋一, 柳有起, 大野義章

    日本物理学会 第66回年次大会  2011.3 

     More details

    Language:Japanese   Presentation type:Poster presentation  

    Venue:新潟大学  

    researchmap

  • 鉄系超伝導体のd-p模型における格子-軌道結合によるs++波超伝導

    柳有起, 山川洋一, 安立奈緒子, 大野義章

    日本物理学会 第66回年次大会  2011.3 

     More details

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:新潟大学  

    researchmap

  • 結晶場状態を考慮した重い電子系に対する動的平均場理論

    山田武見, 大野義章

    日本物理学会 第66回年次大会  2011.3 

     More details

    Language:Japanese   Presentation type:Poster presentation  

    Venue:新潟大学  

    researchmap

  • 動的平均場による2軌道ハバード模型の磁気秩序と軌道秩序

    林健太, 山田武見, 布施貴裕, 山川洋一, 柳有起, 大野義章

    日本物理学会 第66回年次大会  2011.3 

     More details

    Language:Japanese   Presentation type:Poster presentation  

    Venue:新潟大学  

    researchmap

  • Phase Diagram of Magnetic and Orbital Orders in the Two-Dimensional 16-Band d-p Model for Iron Pnictides International conference

    Naoko Adachi, Yuki Yanagi, Youichi Yamakawa, Yoshiaki Ono

    International Workshop on Novel Superconductors and Super Materials 2011  2011.3 

     More details

    Language:English   Presentation type:Poster presentation  

    Venue:Tokyo, Japan  

    researchmap

  • Effect of Orbital-Lattice Coupling on the Superconductivity in the d-p Model for Iron Pnictides International conference

    Yuki Yanagi, Youichi Yamakawa, Naoko Adachi, Yoshiaki Ono

    International Workshop on Novel Superconductors and Super Materials 2011  2011.3 

     More details

    Language:English   Presentation type:Poster presentation  

    Venue:Tokyo, Japan  

    researchmap

  • Ferro-orbital Order, Structural Transition and S++-wave Superconductivity in International conference

    Yoshiaki Ono, Yuki Yanagi, Youichi Yamakawa, Naoko Adachi

    International Workshop on Novel Superconductors and Super Materials 2011  2011.3 

     More details

    Language:English   Presentation type:Oral presentation (invited, special)  

    Venue:Tokyo, Japan  

    researchmap

  • Theoretical Study on Orbital Order, Structural Transition and Superconductivity in Iron Pnictides International conference

    Yoshiaki Ono, Yuki Yanagi, Youichi Yamakawa, Naoko Adachi

    2nd Kanazawa U - JAIST joint meeting on computational science  2011.2 

     More details

    Language:English   Presentation type:Oral presentation (invited, special)  

    Venue:Kanazawa, Japan  

    researchmap

  • Effects of dynamical Jahn-Teller phonons on the charge states in a silicon vacancy International conference

    Youichi Yamakawa, Takemi Yamada, Yoshiaki Ono

    The Forum on the Science and Technology of Silicon Materials 2010  2010.11 

     More details

    Language:English   Presentation type:Poster presentation  

    Venue:Okayama, Japan  

    researchmap

  • Green's function approach for the electronic state in a silicon vacancy International conference

    Takemi Yamada, Youichi Yamakawa, Yoshiaki Ono

    The Forum on the Science and Technology of Silicon Materials 2010  2010.11 

     More details

    Language:English   Presentation type:Poster presentation  

    Venue:Okayama, Japan  

    researchmap

  • 動的平均場理論による近藤半導体の電子状態

    山田武見, 布施貴裕, 大野義章

    日本物理学会 2010年秋季大会  2010.9 

     More details

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:大阪府立大学  

    researchmap

  • シリコン原子空孔の電子状態に対するスピン軌道相互作用の効果II

    山田武見, 山川洋一, 大野義章

    日本物理学会 2010年秋季大会  2010.9 

     More details

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:大阪府立大学  

    researchmap

  • 2次元16バンドd-p模型の磁気・軌道・電荷秩序と電子格子相互作用の効果

    安立奈緒子, 山川洋一, 柳有起, 大野義章

    日本物理学会 2010年秋季大会  2010.9 

     More details

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:大阪府立大学  

    researchmap

  • 非調和ハバード・ホルスタイン模型の相図

    布施貴裕, 大野義章

    日本物理学会 2010年秋季大会  2010.9 

     More details

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:大阪府立大学  

    researchmap

  • シリコン原子空孔における強相関・強結合量子状態とスピン軌道相互作用の効果

    山川洋一, 山田武見, 大野義章

    日本物理学会 2010年秋季大会  2010.9 

     More details

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:大阪府立大学  

    researchmap

  • 鉄系超伝導体のd-p模型におけるd-pサイト間斥力Updの効果

    柳有起, 山川洋一, 安立奈緒子, 大野義章

    日本物理学会 2010年秋季大会  2010.9 

     More details

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:大阪府立大学  

    researchmap

  • 鉄系超伝導体に対する2軌道ハバード模型の動的平均場理論

    林健太, 布施貴裕, 山川洋一, 柳有起, 山田武見, 大野義章

    日本物理学会 2010年秋季大会  2010.9 

     More details

    Language:Japanese   Presentation type:Poster presentation  

    Venue:大阪府立大学  

    researchmap

  • Rattling-Induced Heavy Fermion State in the Anharmonic Holstein Model International conference

    Takahiro Fuse, Yoshiaki Ono

    International Conference on Heavy Electrons  2010.9 

     More details

    Language:English   Presentation type:Poster presentation  

    Venue:Tokyo, Japan  

    researchmap

  • Dynamical Mean-Field Study of Metamagnetism in Heavy Fermion Systems International conference

    Takemi Yamada, Yoshiaki Ono

    International Conference on Heavy Electrons  2010.9 

     More details

    Language:English   Presentation type:Poster presentation  

    Venue:Tokyo, Japan  

    researchmap

  • 動的平均場理論による重い電子系のメタ磁性II

    山田武見, 大野義章

    日本物理学会 第65回年次大会  2010.3 

     More details

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:岡山大学  

    researchmap

  • 鉄系超伝導体のd-p模型における磁気・軌道・電荷秩序

    安立奈緒子, 山川洋一, 柳有起, 大野義章

    日本物理学会 第65回年次大会  2010.3 

     More details

    Language:Japanese   Presentation type:Poster presentation  

    Venue:岡山大学  

    researchmap

  • 鉄系超伝導体に対するd-p模型のs±とs++波の超伝導相図

    柳有起, 山川洋一, 安立奈緒子, 大野義章

    日本物理学会 第65回年次大会  2010.3 

     More details

    Language:Japanese   Presentation type:Poster presentation  

    Venue:岡山大学  

    researchmap

  • ハバード・ホルスタイン模型におけるバイポーラロン転移と超伝導II

    布施貴裕, 大野義章

    日本物理学会 第65回年次大会  2010.3 

     More details

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:岡山大学  

    researchmap

  • 磁性半導体(Zn1-xTix)Oの強磁性と強相関効果

    鈴木良, 布施貴裕, 大野義章

    日本物理学会 第65回年次大会  2010.3 

     More details

    Language:Japanese   Presentation type:Poster presentation  

    Venue:岡山大学  

    researchmap

  • シリコン原子空孔における電子相関-電子フォノン非断熱効果と弾性ソフト化III

    山川洋一, 山田武見, 大野義章

    日本物理学会 第65回年次大会  2010.3 

     More details

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:岡山大学  

    researchmap

  • 鉄ニクタイドにおける共鳴非弾性X線散乱の理論的研究

    川村知生, 布施貴裕, 大野義章

    日本物理学会 2009年秋季大  2009.9 

     More details

    Language:Japanese   Presentation type:Poster presentation  

    Venue:熊本大学  

    researchmap

  • NaxCoO2の電子状態と輸送特性における強磁性スピン揺らぎの効果

    柳有起, 大野義章

    日本物理学会 2009年秋季大  2009.9 

     More details

    Language:Japanese   Presentation type:Poster presentation  

    Venue:熊本大学  

    researchmap

  • 2次元16バンドd-p模型による鉄ニクタイド系の超伝導機構II

    柳有起, 山川洋一, 大野義章

    日本物理学会 2009年秋季大  2009.9 

     More details

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:熊本大学  

    researchmap

  • 層状コバルト酸化物Na0.5CoO2の二段転移と強相関効果II

    渡邉直浩, 山川洋一, 大野義章

    日本物理学会 2009年秋季大  2009.9 

     More details

    Language:Japanese   Presentation type:Poster presentation  

    Venue:熊本大学  

    researchmap

  • シリコン原子空孔におけるスピン軌道相互作用と電子フォノン相互作用の効果

    山田武見, 山川洋一, 大野義章

    日本物理学会 2009年秋季大  2009.9 

     More details

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:熊本大学  

    researchmap

  • 希薄磁性半導体の電子状態と強相関効果

    鈴木良, 布施貴裕, 大野義章

    日本物理学会 2009年秋季大  2009.9 

     More details

    Language:Japanese   Presentation type:Poster presentation  

    Venue:熊本大学  

    researchmap

  • 非調和ホルスタイン・アンダーソン格子の重い電子状態と超伝導

    大野義章, 川村知生, 布施貴裕

    日本物理学会 2009年秋季大  2009.9 

     More details

    Language:Japanese   Presentation type:Poster presentation  

    Venue:熊本大学  

    researchmap

  • 動的平均場理論による重い電子系のメタ磁性

    山田武見, 布施貴裕, 大野義章

    日本物理学会 2009年秋季大  2009.9 

     More details

    Language:Japanese   Presentation type:Poster presentation  

    Venue:熊本大学  

    researchmap

  • シリコン原子空孔における電子相関-電子フォノン非断熱効果と弾性ソフト化II

    山川洋一, 山田武見, 大野義章

    日本物理学会 2009年秋季大  2009.9 

     More details

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:熊本大学  

    researchmap

  • ハバード・ホルスタイン模型におけるバイポーラロン転移と超伝導

    布施貴裕, 大野義章

    日本物理学会 2009年秋季大  2009.9 

     More details

    Language:Japanese   Presentation type:Poster presentation  

    Venue:熊本大学  

    researchmap

  • Phase Diagram of the Two-dimensional 16-band d-p Model for Iron-based Superconductors International conference

    Yuki Yanagi, Youichi Yamakawa, Yoshiaki Ono

    9th International Conference on Materials and Mechanisms of Superconductivity  2009.9 

     More details

    Language:English   Presentation type:Poster presentation  

    Venue:Tokyo, Japan  

    researchmap

  • A Possible Bipolaronic Transition in β-pyrochlore Compounds International conference

    Takahiro Fuse, Yoshiaki Ono

    9th International Conference on Materials and Mechanisms of Superconductivity  2009.9 

     More details

    Language:English   Presentation type:Poster presentation  

    Venue:Tokyo, Japan  

    researchmap

  • Effects of ferromagnetic fluctuations on the electric and thermal transport properties in NaxCoO2 International conference

    Yuki Yanagi, Yoshiaki Ono

    International Conference on Magnetism  2009.7 

     More details

    Language:English   Presentation type:Poster presentation  

    Venue:Karlsruhe, Germany  

    researchmap

  • Effect of the spin-orbit interaction and the electron phonon coupling on the electronic state in a silicon vacancy International conference

    Takemi Yamada, Youichi Yamakawa, Yoshiaki Ono

    International Conference on Magnetism  2009.7 

     More details

    Language:English   Presentation type:Poster presentation  

    Venue:Karlsruhe, Germany  

    researchmap

  • Antiferromagnetic, Charge and Orbital Order in Na0.5CoO2 Based on the Two Dimensional 11 Bands d-p Model International conference

    Youichi Yamakawa, Naohiro Watanabe, Yoshiaki Ono

    International Conference on Magnetism  2009.7 

     More details

    Language:English   Presentation type:Poster presentation  

    Venue:Karlsruhe, Germany  

    researchmap

  • Low temperature first order transition in the Holstein model: A mechanism of rattling transition in β-pyrochlore KOs2O6 International conference

    Yoshiaki Ono, Takahiro Fuse

    International Conference on Magnetism  2009.7 

     More details

    Language:English   Presentation type:Poster presentation  

    Venue:Karlsruhe, Germany  

    researchmap

  • FeAs系超伝導体の試料育成と圧力・置換効果

    光田暁弘, 的場智広, 荒岡信隆, 石川文洋, 大村彩子, 小澤忠, 山田裕, 大野義章, 和田裕文

    日本物理学会 第64回年次大会  2009.3 

     More details

    Language:Japanese   Presentation type:Poster presentation  

    Venue:立教大学  

    researchmap

  • ハニカム格子系Li2RuO3における新しい相転移機構

    三浦陽子, 佐藤正俊, 山川洋一, 幅口達朗, 大野義章

    日本物理学会 第64回年次大会  2009.3 

     More details

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:立教大学  

    researchmap

  • 2次元16バンドd-p模型による鉄ニクタイド系の超伝導機構

    柳有起, 山川洋一, 大野義章

    日本物理学会 第64回年次大会  2009.3 

     More details

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:立教大学  

    researchmap

  • ハバード-ホルスタイン模型における有限温度の1次転移

    布施貴裕, 大野義章

    日本物理学会 第64回年次大会  2009.3 

     More details

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:立教大学  

    researchmap

  • LaFeAsOに対する有効d-p模型の導出と電子状態

    山川洋一, 柳有紀, 大野義章

    日本物理学会 第64回年次大会  2009.3 

     More details

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:立教大学  

    researchmap

  • シリコン原子空孔の電子状態に対するスピン軌道相互作用の効果

    山田武見, 山川洋一, 大野義章

    日本物理学会 第64回年次大会  2009.3 

     More details

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:立教大学  

    researchmap

  • 希薄磁性半導体(Zn1-xTMx)Oの電子状態と強相関効果

    鈴木良, 山川洋一, 大野義章

    日本物理学会 第64回年次大会  2009.3 

     More details

    Language:Japanese   Presentation type:Poster presentation  

    Venue:立教大学  

    researchmap

  • ホルスタイン模型における非調和フォノンの効果と温度依存性

    川村知生, 布施貴裕, 大野義章

    日本物理学会 第64回年次大会  2009.3 

     More details

    Language:Japanese   Presentation type:Poster presentation  

    Venue:立教大学  

    researchmap

  • 層状コバルト酸化物Na0.5CoO2の二段転移と強相関効果

    渡邉直浩, 山川洋一, 大野義章

    日本物理学会 第64回年次大会  2009.3 

     More details

    Language:Japanese   Presentation type:Poster presentation  

    Venue:立教大学  

    researchmap

  • ホルスタイン模型における有限温度の1次転移

    布施貴裕, 川村知生, 大野義章

    日本物理学会 2008年秋季大会  2008.9 

     More details

    Language:Japanese   Presentation type:Poster presentation  

    Venue:岩手大学  

    researchmap

  • ホルスタイン模型における非調和フォノンの効果と超伝導

    川村知生, 三本啓輔, 大野義章

    日本物理学会 2008年秋季大会  2008.9 

     More details

    Language:Japanese   Presentation type:Poster presentation  

    Venue:岩手大学  

    researchmap

  • シリコン原子空孔における電子相関-電子フォノン非断熱効果と弾性ソフト化

    山川洋一, 山田武見, 大野義章

    日本物理学会 2008年秋季大会  2008.9 

     More details

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:岩手大学  

    researchmap

  • シリコン原子空孔における電荷状態の拡がりと弾性ソフト化

    山田武見, 山川洋一, 大野義章

    日本物理学会 2008年秋季大会  2008.9 

     More details

    Language:Japanese   Presentation type:Poster presentation  

    Venue:岩手大学  

    researchmap

  • Off-Center型非調和ポテンシャルにおける量子状態とラットリング

    布施貴裕, 山川洋一, 三本啓輔, 大野義章

    日本物理学会 2008年秋季大会  2008.9 

     More details

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:岩手大学  

    researchmap

  • 2軌道ハバードモデルの超伝導-オキシニクタイド系の超伝導機構-

    佐野和博, 大野義章

    日本物理学会 2008年秋季大会  2008.9 

     More details

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:岩手大学  

    researchmap

  • 2次元三角格子d-p模型によるNa0.5CoO2の2段転移と磁場依存性

    山川洋一, 大野義章

    日本物理学会 2008年秋季大会  2008.9 

     More details

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:岩手大学  

    researchmap

  • シリコン原子空孔における電荷状態の広がりと強相関・強結合効果

    大野義章

    日本物理学会 2008年秋季大会  2008.9 

     More details

    Language:Japanese   Presentation type:Symposium, workshop panel (nominated)  

    Venue:岩手大学  

    researchmap

  • 2次元16バンドd-p模型によるオキシニクタイド超伝導体の電子状態

    柳有起, 山川洋一, 大野義章

    日本物理学会 2008年秋季大会  2008.9 

     More details

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:岩手大学  

    researchmap

  • Cluster Model Calculations for Charge States of a Silicon Vacancy International conference

    Youichi Yamakawa, Yoshiaki Ono

    25th International Conference on Low Temperature Physics  2008.8 

     More details

    Language:English   Presentation type:Poster presentation  

    Venue:Amsterdam, Netherlands  

    researchmap

  • Electronic states and pairing symmetry in the two-dimensional 16 band d-p model for iron-based superconductor International conference

    Yuki Yanagi, Youichi Yamakawa, Yoshiaki Ono

    International Symposium on Fe-Pnictide Superconductors  2008.6 

     More details

    Language:English   Presentation type:Poster presentation  

    Venue:Tokyo, Japan  

    researchmap

  • ハニカム格子系Li2RuO3の電子状態と金属絶縁体転移

    幅口達朗, 大野義章, 三浦陽子, 佐藤正俊

    日本物理学会 第63回年次大会  2008.3 

     More details

    Language:Japanese   Presentation type:Poster presentation  

    Venue:近畿大学  

    researchmap

  • ホルスタイン模型における非調和フォノンの効果

    川村知生, 三本啓輔, 大野義章

    日本物理学会 第63回年次大会  2008.3 

     More details

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:近畿大学  

    researchmap

  • 複数のスピン状態を含む拡張スレーブボソン法によるコバルト酸化物の電子状態

    渡邉直浩, 大野義章

    日本物理学会 第63回年次大会  2008.3 

     More details

    Language:Japanese   Presentation type:Poster presentation  

    Venue:近畿大学  

    researchmap

  • 3軌道ハバード模型によるNaxCoO2の電子状態

    柳有起, 大野義章

    日本物理学会 第63回年次大会  2008.3 

     More details

    Language:Japanese   Presentation type:Poster presentation  

    Venue:近畿大学  

    researchmap

  • グリーン関数を用いたシリコン原子空孔における局所電子状態

    山田武見, 山川洋一, 大野義章

    日本物理学会 第63回年次大会  2008.3 

     More details

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:近畿大学  

    researchmap

  • シリコン結晶中の原子空孔における強相関-強結合量子状態III

    山川洋一, 三本啓輔, 大野義章

    日本物理学会 第63回年次大会  2008.3 

     More details

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:近畿大学  

    researchmap

  • 拡張周期的アンダーソン模型の価数揺らぎと重い電子状態

    布施貴裕, 三本啓輔, 大野義章

    日本物理学会 第63回年次大会  2008.3 

     More details

    Language:Japanese   Presentation type:Poster presentation  

    Venue:近畿大学  

    researchmap

  • 拡張ホルスタイン模型における重い電子状態

    三本啓輔, 大野義章

    日本物理学会 第63回年次大会  2008.3 

     More details

    Language:Japanese   Presentation type:Poster presentation  

    Venue:近畿大学  

    researchmap

  • Electronic state of a single vacancy in silicon crystal International conference

    Takemi Yamada, Youichi Yamakawa, Yoshiaki Ono

    The Forum on the Science and Technology of Silicon Materials 2007  2007.11 

     More details

    Language:English   Presentation type:Poster presentation  

    Venue:Niigata, Japan  

    researchmap

  • Effects of electron correlation and nonadiabatic electron-phonon interaction on vacancy orbitals in silicon International conference

    Youichi Yamakawa, Yoshiaki Ono

    The Forum on the Science and Technology of Silicon Materials 2007  2007.11 

     More details

    Language:English   Presentation type:Poster presentation  

    Venue:Niigata, Japan  

    researchmap

  • Effects of Electron Correlation and Electron-phonon Coupling on the quantum state of a Silicon Vacancy International conference

    Youichi Yamakawa, Keisuke Mitsumoto, Yoshiaki Ono

    International Conference on "New Quantum Phenomena in Skutterudite and Related Systems"  2007.9 

     More details

    Language:English   Presentation type:Poster presentation  

    Venue:Kobe, Japan  

    researchmap

  • Rattling motion of guest ions under anharmonic potentials realized in a strongly coupled electron-phonon system International conference

    Yoshiaki Ono, Takahiro Fuse, Keisuke Mitsumoto

    International Conference on "New Quantum Phenomena in Skutterudite and Related Systems"  2007.9 

     More details

    Language:English   Presentation type:Poster presentation  

    Venue:Kobe, Japan  

    researchmap

  • Heavy-fermion state in the extended two-orbital Anderson lattice model coupled with two degenerated Jahn-Teller phonons International conference

    Keisuke Mitsumoto, Yoshiaki Ono

    International Conference on "New Quantum Phenomena in Skutterudite and Related Systems"  2007.9 

     More details

    Language:English   Presentation type:Poster presentation  

    Venue:Kobe, Japan  

    researchmap

  • Dynamical mean-field study of valence fluctuations and heavy fermions in the periodic Anderson model International conference

    Takahiro Fuse, Keisuke Mitsumoto, Yoshiaki Ono

    International Conference on "New Quantum Phenomena in Skutterudite and Related Systems"  2007.9 

     More details

    Language:English   Presentation type:Poster presentation  

    Venue:Kobe, Japan  

    researchmap

  • 動的平均場理論による周期的アンダーソン模型の価数揺らぎと電子状態II

    布施貴裕, 三本啓輔, 大野義章

    日本物理学会 第62回年次大会  2007.9 

     More details

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:北海道大学  

    researchmap

  • 2次元三角格子d-p模型によるNa0.5CoO2の磁気・電荷・軌道秩序

    山川洋一, 大野義章

    日本物理学会 第62回年次大会  2007.9 

     More details

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:北海道大学  

    researchmap

  • NaxCoO2の電子状態における強磁性スピン揺らぎの効果II

    柳有起, 大野義章

    日本物理学会 第62回年次大会  2007.9 

     More details

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:北海道大学  

    researchmap

  • 動的平均場理論による多軌道アンダーソン格子模型の電子状態II

    三本啓輔, 大野義章

    日本物理学会 第62回年次大会  2007.9 

     More details

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:北海道大学  

    researchmap

  • シリコンの原子空孔における電子状態

    大野義章, 山川洋一, 山田武見

    日本物理学会 第62回年次大会  2007.9 

     More details

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:北海道大学  

    researchmap

  • シリコン原子空孔における局所電子状態と磁場依存性

    山田武見, 山川洋一, 大野義章

    日本物理学会 第62回年次大会  2007.9 

     More details

    Language:Japanese   Presentation type:Poster presentation  

    Venue:北海道大学  

    researchmap

  • ハニカム格子系Li2RuO3の電子状態と金属絶縁体転移

    幅口達朗, 大野義章, 三浦陽子, 佐藤正俊

    日本物理学会 第62回年次大会  2007.9 

     More details

    Language:Japanese   Presentation type:Poster presentation  

    Venue:北海道大学  

    researchmap

  • 周期的アンダーソン・ホルスタイン模型における非調和フォノンの効果

    川村知生, 三本啓輔, 大野義章

    日本物理学会 第62回年次大会  2007.9 

     More details

    Language:Japanese   Presentation type:Poster presentation  

    Venue:北海道大学  

    researchmap

  • ダブルチェーンモデルのスピンギャップ

    佐野和博, 大野義章

    日本物理学会 第62回年次大会  2007.9 

     More details

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:北海道大学  

    researchmap

  • Antiferromagnetic, charge and orbital ordered states of Na0.5CoO2 based on the two-dimensional triangular lattice d-p model International conference

    Youichi Yamakawa, Yoshiaki Ono

    8th International Conference on Spectroscopies in Novel Superconductors  2007.8 

     More details

    Language:English   Presentation type:Poster presentation  

    Venue:Sendai, Japan  

    researchmap

  • Effect of ferromagnetic spin fluctuations on the electronic states in NaxCoO2 based on two-dimensional triangular lattice 11-band d-p model International conference

    Yuki Yanagi, Yoshiaki Ono

    8th International Conference on Spectroscopies in Novel Superconductors  2007.8 

     More details

    Language:English   Presentation type:Poster presentation  

    Venue:Sendai, Japan  

    researchmap

  • Rattling motion and on+off-center potential formation in a strongly coupled electron-phonon system International conference

    Yoshiaki Ono, Takahiro Fuse, Keisuke Mitsumoto

    12th International Conference on Phonon Scattering in Condensed Matter  2007.7 

     More details

    Language:English   Presentation type:Poster presentation  

    Venue:Paris, France  

    researchmap

  • Rattling motion and heavy-fermion behavior in the strongly coupled electron-phonon system International conference

    Keisuke Mitsumoto, Yoshiaki Ono

    Coherence and Incoherence in Strongly Correlated Systems  2007.7 

     More details

    Language:English   Presentation type:Poster presentation  

    Venue:Rome, Italy  

    researchmap

  • Dynamical mean-field study of the heavy-fermion state in the multi-orbital Anderson lattice model coupled with Jahn-Teller phonons International conference

    Keisuke Mitsumoto, Yoshiaki Ono

    The International Conference on Strongly Correlated Electron Systems  2007.5 

     More details

    Language:English   Presentation type:Poster presentation  

    Venue:Houston, USA  

    researchmap

  • 複数のスピン状態を含む拡張スレーブボソン法によるコバルト酸化物の電子状態

    渡邉直浩, 大野義章

    日本物理学会 2007年春季大会  2007.3 

     More details

    Language:Japanese   Presentation type:Poster presentation  

    Venue:鹿児島大学  

    researchmap

  • Off-Center型非調和ポテンシャルにおける量子状態と異常物性

    布施貴裕, 山川洋一, 大野義章

    日本物理学会 2007年春季大会  2007.3 

     More details

    Language:Japanese   Presentation type:Poster presentation  

    Venue:鹿児島大学  

    researchmap

  • NaxCoO2の電子状態における強磁性スピン揺らぎの効果

    柳有起, 大野義章

    日本物理学会 2007年春季大会  2007.3 

     More details

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:鹿児島大学  

    researchmap

  • 2次元三角格子d-p模型によるNa0.5CoO2の磁気秩序と電荷秩序

    山川洋一, 大野義章

    日本物理学会 2007年春季大会  2007.3 

     More details

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:鹿児島大学  

    researchmap

  • 動的平均場理論による多軌道アンダーソン格子模型の電子状態

    三本啓輔, 大野義章

    日本物理学会 2007年春季大会  2007.3 

     More details

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:鹿児島大学  

    researchmap

  • 擬一次元超伝導体Pr2Ba4Cu7O15-δの電子状態と超伝導機構II

    幅口達朗, 大野義章, 佐野和博, 山田裕

    日本物理学会 2007年春季大会  2007.3 

     More details

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:鹿児島大学  

    researchmap

  • 動的平均場理論による周期的アンダーソン模型の価数揺らぎと電子状態

    布施貴裕, 三本啓輔, 大野義章

    日本物理学会 2007年春季大会  2007.3 

     More details

    Language:Japanese   Presentation type:Poster presentation  

    Venue:鹿児島大学  

    researchmap

  • シリコン結晶中の原子空孔における強相関-強結合量子状態II

    山川洋一, 三本啓輔, 大野義章

    日本物理学会 2007年春季大会  2007.3 

     More details

    Language:Japanese   Presentation type:Poster presentation  

    Venue:鹿児島大学  

    researchmap

  • 2次元三角格子d-p模型によるNa0.5CoO2の反強磁性と2段転移

    山川洋一, 大野義章

    日本物理学会 2006年秋季大会  2006.9 

     More details

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:千葉大学  

    researchmap

  • ダブルチェーンt-JモデルによるPr2Ba4Cu7O15-δの超伝導

    佐野和博, 大野義章

    日本物理学会 2006年秋季大会  2006.9 

     More details

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:千葉大学  

    researchmap

  • 動的平均場理論によるBドープダイヤモンドの電子状態と超伝導

    三本啓輔, 大野義章

    日本物理学会 2006年秋季大会  2006.9 

     More details

    Language:Japanese   Presentation type:Poster presentation  

    Venue:千葉大学  

    researchmap

  • 擬一次元超伝導体Pr2Ba4Cu7O15-δの電子状態と超伝導機構

    幅口達朗, 大野義章, 佐野和博, 山田裕

    日本物理学会 2006年秋季大会  2006.9 

     More details

    Language:Japanese   Presentation type:Poster presentation  

    Venue:千葉大学  

    researchmap

  • 充填スクッテルダイト化合物におけるラットリングと伝導電子の結合の理論

    布施貴裕, 三本啓輔, 山川洋一, 大野義章

    日本物理学会 2006年秋季大会  2006.9 

     More details

    Language:Japanese   Presentation type:Poster presentation  

    Venue:千葉大学  

    researchmap

  • スレーブボソン法によるペロブスカイト型コバルト酸化物の電子状態

    渡邉直浩, 大野義章

    日本物理学会 2006年秋季大会  2006.9 

     More details

    Language:Japanese   Presentation type:Poster presentation  

    Venue:千葉大学  

    researchmap

  • NaxCoO2・yH2Oにおけるペアトランスファー機構によるs波超伝導

    柳有起, 大野義章

    日本物理学会 2006年秋季大会  2006.9 

     More details

    Language:Japanese   Presentation type:Poster presentation  

    Venue:千葉大学  

    researchmap

  • シリコン結晶中の原子空孔における強相関-強結合量子状態

    山川洋一, 三本啓輔, 大野義章

    日本物理学会 2006年秋季大会  2006.9 

     More details

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:千葉大学  

    researchmap

  • Heavy fermion state in the periodic Anderson-Holstein model away from half filling International conference

    Keisuke Mitsumoto, Yoshiaki Ono

    The 17th International Conference on Magnetism  2006.8 

     More details

    Language:English   Presentation type:Poster presentation  

    Venue:Kyoto, Japan  

    researchmap

  • Ferromagnetism and superconductivity in the one-dimensional multi-orbital Hubbard model International conference

    Kazuhiro Sano, Yoshiaki Ono

    The 17th International Conference on Magnetism  2006.8 

     More details

    Language:English   Presentation type:Poster presentation  

    Venue:Kyoto, Japan  

    researchmap

  • Nonadiabatic interaction between electrons and Jahn-Teller distortions in a silicon vacancy International conference

    Youichi Yamakawa, Keisuke Mitsumoto, Yoshiaki Ono

    The 17th International Conference on Magnetism  2006.8 

     More details

    Language:English   Presentation type:Poster presentation  

    Venue:Kyoto, Japan  

    researchmap

  • Metal insulator transition and spin state transition in the two-orbital Hubbard model International conference

    Yoshiaki Ono

    The 17th International Conference on Magnetism  2006.8 

     More details

    Language:English   Presentation type:Poster presentation  

    Venue:Kyoto, Japan  

    researchmap

  • Correlation Effects on Fermi Surface and Magnetism in the Triangular Lattice d-p Model for Layered Cobaltates International conference

    Yoshiaki Ono, Naohiro Watanabe, Youichi Yamakawa

    Highly Frustrated Magnetism 2006  2006.8 

     More details

    Language:English   Presentation type:Poster presentation  

    Venue:Osaka, Japan  

    researchmap

  • Superconductivity in the One-Dimensional Two-Orbital Hubbard Model with Finite Band Splitting International conference

    Kazuhiro Sano, Yoshiaki Ono

    Highly Frustrated Magnetism 2006  2006.8 

     More details

    Language:English   Presentation type:Poster presentation  

    Venue:Osaka, Japan  

    researchmap

  • Electronic state of NaxCoO2 based on the two dimensional triangular lattice d-p model International conference

    Youichi Yamakawa, Yoshiaki Ono

    Highly Frustrated Magnetism 2006  2006.8 

     More details

    Language:English   Presentation type:Poster presentation  

    Venue:Osaka, Japan  

    researchmap

  • Electronic states and metal-insulator transition in the triangular lattice d-p model for layered cobaltates International conference

    Yoshiaki Ono

    The 8th International Conference on Materials and Mechanisms of Superconductivity and High Temperature Superconductors  2006.7 

     More details

    Language:English   Presentation type:Poster presentation  

    Venue:Dresden, Germany  

    researchmap

  • Doping-dependence of the electronic state in the periodic Anderson-Holstein model International conference

    Keisuke Mitsumoto, Yoshiaki Ono

    The International Symposium on Anomalous Quantum Materials 2006 and The 5-th Asia-Pacific Workshop  2006.6 

     More details

    Language:English   Presentation type:Poster presentation  

    Venue:Okinawa, Japan  

    researchmap

  • Correlation effects on Fermi surface and magnetism of NaxCoO2 International conference

    Yoshiaki Ono, Naohiro Watanabe, Youichi Yamakawa

    The International Symposium on Anomalous Quantum Materials 2006 and The 5-th Asia-Pacific Workshop  2006.6 

     More details

    Language:English   Presentation type:Poster presentation  

    Venue:Okinawa, Japan  

    researchmap

  • 2次元三角格子d-p模型によるNaxCoO2の電子状態

    山川洋一, 大野義章

    日本物理学会 第61回年次大会  2006.3 

     More details

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:愛媛大学  

    researchmap

  • 11バンドd-p模型によるNaxCoO2の電子相関とフェルミ面

    大野義章, 渡邉直浩

    日本物理学会 第61回年次大会  2006.3 

     More details

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:愛媛大学  

    researchmap

  • 動的平均場理論によるBドープダイヤモンドの電子状態

    三本啓輔, 大野義章

    日本物理学会 第61回年次大会  2006.3 

     More details

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:愛媛大学  

    researchmap

▶ display all

Awards

  • JPSJ: Papers of Editors’ Choice

    2010.12   Physical Society of Japan  

    Y. Yanagi, Y. Yamakawa, N. Adachi, Yoshiaki Ono

     More details

    Award type:Honored in official journal of a scientific society, scientific journal  Country:Japan

    researchmap

  • Physica C: Top Cited Article 2005-2010

    2010.10   Elsevier  

    K. Mitsumoto, Y. Ono

     More details

    Award type:Honored in official journal of a scientific society, scientific journal 

    researchmap

Research Projects

  • 多バンド系の励起子相におけるFFLO状態と新奇超伝導の理論

    2017.4 - 2020.3

    日本学術振興会  科学研究費助成事業  基盤研究(C)

      More details

    Grant type:Competitive

    Grant amount:\3400000 ( Direct Cost: \2380000 、 Indirect Cost:\1020000 )

    researchmap

  • 多バンド系における新奇励起子相の理論

    2016.4

    科学研究費補助金 

      More details

    Grant type:Competitive

    researchmap

  • 多バンド系における電子相関と軌道-格子結合の協力効果と超伝導機構

    2014.4 - 2017.3

    日本学術振興会  科学研究費助成事業  基盤研究(C)

      More details

    Grant type:Competitive

    Grant amount:\3700000 ( Direct Cost: \2590000 、 Indirect Cost:\1110000 )

    鉄系超伝導体の理論研究を通して構築された計算手法を用いて、電子相関と軌道-格子結合の協力効果が重要と考えられる多バンド系を調べた。A15型超伝導体の第一原理計算から導出した36バンドd-p模型に基づき、サイト間d-pクーロン相互作用の効果が構造相転移(マルテンサイト変体)を共に説明する軌道秩序を記述するとともに、その揺らぎがHigh-Tcの起源となることを示した。また、Ta2NiSe5に対する3鎖ハバード模型を調べた結果、高圧半金属相ではFulde-Ferrell-Larkin-Ovchinnikov(FFLO)励起子相が発現し、その揺らぎによってFFLO超伝導が導かれることが分かった。

    researchmap

  • 多バンド系における高温超伝導機構

    2013.4

    科学研究費補助金 

      More details

    Grant type:Competitive

    researchmap

  • 鉄系高温超伝導の発現機構と対称性

    2011.4 - 2014.3

    日本学術振興会  科学研究費助成事業  基盤研究(C)

      More details

    Grant type:Competitive

    Grant amount:\3900000 ( Direct Cost: \2730000 、 Indirect Cost:\1170000 )

    鉄系高温超伝導体の超伝導機構として、これまで反強磁性揺らぎを媒介とするs±波超伝導と軌道揺らぎを媒介とするs++波超伝導が提案されており、論争が続いている。どちらの超伝導が実現しているかを解明するには、従来の研究で用いられてきたRPAを超えて相関効果をより正確に取り扱う必要がある。本研究では局所相関と空間相関を共に十分に考慮し、且つ複雑な格子模型にも適用可能な量子多体計算手法を開発する。得られた手法を鉄系超伝導体の基本模型(多軌道ハバード(d-p)ホルスタイン模型)に適用し、超伝導の発現機構と対称性を解明する。特に、電子相関と軌道-格子相関の協力効果によって増強される軌道揺らぎを媒介とする新しい超伝導機構の可能性を検証する。その際、各物質を記述する低エネルギー有効模型を第一原理計算に基づいて導出し、磁気秩序、軌道秩序、構造転移の相図や超伝導転移温度Tcの物質依存性を説明する。

    researchmap

  • 鉄系高温超伝導のメカニズム解明とHigh-Tc物質設計

    2011.4 - 2012.3

    財団法人内田エネルギー科学振興財団  受託研究(一般受託研究) 

      More details

    Grant type:Competitive

    Grant amount:\400000

    researchmap

  • 鉄プニクタイド系超伝導研究と物質設計

    2010.10 - 2012.3

    JST  受託研究(一般受託研究) 

      More details

    Grant type:Competitive

    Grant amount:\4100000

    researchmap

  • 鉄系高温超伝導の発現機構

    2008.9

    科学研究費補助金 

      More details

    Grant type:Competitive

    researchmap

  • 新しいエネルギー変換材料開発のための物質設計

    2006.4 - 2007.3

    財団法人内田エネルギー科学振興財団  受託研究(一般受託研究) 

      More details

    Grant type:Competitive

    Grant amount:\800000

    researchmap

  • シリコン原子空孔の理論

    2005.4 - 2012.3

    科学研究費補助金 

      More details

    Grant type:Competitive

    researchmap

  • コバルト酸化物における多元要素の量子多体効果が導く異常物性と新奇超伝導機構の理論

    2005.4 - 2008.3

    日本学術振興会  科学研究費助成事業  基盤研究(C)

      More details

    Grant type:Competitive

    Grant amount:\3500000 ( Direct Cost: \3230000 、 Indirect Cost:\270000 )

    Na_xCoO_2・yH_2Oにおける超伝導の発見以来、その対称性については様々な可能性が特に理論的に議論されてきたが、ナイトシフトや不純物効果の実験によれば一重項s波の可能性が高いと考えられる。本研究では、この系の超伝導を、Coのd軌道5個とCo面の上下の酸素面にあるp軌道それぞれ3個の合計11個の軌道を含む2次元三角格子llバンドd-p模型に基づいて調べる。軌道内のクーロン相互作用U、軌道間のクーロン相互作用U'、フント則結合Jによる電子相関効果を、絶対零度ではGutzwiller近似に相当するKotliar-Ruckensteinのスレーブボソン法を用いて考慮し、Na_xCoO_2では電子相関効果によってE_gバンドは押し下げられ6個のホールポケットは消失し、A_<lg>バンドの大きなホールフェルミ面のみ残ること、また、H_2Oが挿入されるとCo面と酸素面の間隔が縮まりtrigonal歪みが増大することにより、E_gバンドが押し上げられ6個のホールポケットが出現することを示した。さらに、クーロン相互作用の軌道間ペア

    researchmap

  • コバルト酸化物の電子状態の理論的研究

    2005.4 - 2008.3

    東北大学金属材料研究所  共同研究(国内共同研究) 

      More details

    Grant type:Competitive

    researchmap

  • コバルト酸化物の電子状態と超伝導の理論

    2005.4 - 2007.3

    文部科学省  科学研究費助成事業  特定領域研究

      More details

    Grant type:Competitive

    Grant amount:\2100000 ( Direct Cost: \2100000 )

    Na_xCoO_2・yH_2Oにおける超伝導の発見を契機に、その母物質Nax_CoO_2の電子状態が精力的に研究され、顕著なドーピング依存性が明らかにされつつある。特にx=0.5では、Naの1次元整列のもとで、面内反強磁性(T_<c1>-=87K)と金属絶縁体転移(T_<c2>=53K)の興味ある2段転移を示すが、後者の起源については未だ明らかにされていない。そこで本研究では、2次元三角格子11バンドd-p模型を用いて層状コバルト酸化物Na_<0.5>CoO_2のCoO_2面の電子状態を調べた。Tight-bindingのパラメータはSinghのLDAバンド計算の結果を再現するように決め、Coサイトのクーロン相互作用は、軌道内及び軌道間の直接項U,U'、交換相互作用J、及びペアトランスファーJ'をHartree-Fock近似の範囲内で考慮した。さらに、x=0.5で起こるNaイオンの1次元整列の効果を、CoO_2面におけるCoの原子準位の変化として取り入れた。Naの1次元整列の効果によってフェルミ面のネスティングが増加し、フラストレーションが解消され反強磁性が出現することを明

    researchmap

  • モット転移近傍におけるフォノン、軌道、乱れの効果

    2002.4 - 2005.3

    日本学術振興会  科学研究費助成事業  基盤研究(C)

      More details

    Grant type:Competitive

    Grant amount:\3900000 ( Direct Cost: \3900000 )

    1.軌道自由度のあるハバード模型のモット転移を動的平均場理論により調べた。フント則結合Jの効果により、モット転移の臨界相互作用U_cが急速に小さくなる。また、J=0では2次転移としておこるモット転移がJ≠0では1次転移へと変化する。
    2.軌道自由度のある1次元ハバード模型を数値的厳密対角化法により調べた。フント則結合Jとクーロン相互作用Uの共に大きな強相関領域で実現する完全強磁性は、結晶場分裂Δの効果により不完全強磁性へと変化する。さらに、不完全強磁性近傍の金属状態では超伝導が実現する。
    3.オンサイトのクーロン相互作用Uに加えて、最近接サイト間のクーロン相互作用Vをもつ1次元拡張ハバード模型の金属絶縁体転移を、数値的厳密対角化法により調べた。有限系に対する厳密対角化の結果を初期値として繰り込み群の方程式に代入することにより、電荷ギャップや臨界指数をU-V平面上で精度良く求めた。
    4.ハバード相互作用Uと電子フォノン相互作用gの全領

    researchmap

  • コバルト酸化物の電子状態と超伝導の理論

    2000.4 - 2008.3

    科学研究費補助金 

      More details

    Grant type:Competitive

    researchmap

  • 強結合電子フォノン系の理論

    1999.11

    科学研究費補助金 

      More details

    Grant type:Competitive

    researchmap

  • モット転移近傍における局所相関とサイト間相関

    1999.4 - 2001.3

    日本学術振興会  科学研究費助成事業  奨励研究

      More details

    Grant type:Competitive

    Grant amount:\2300000 ( Direct Cost: \2300000 )

    1、絶対零度におけるモット転移近傍の臨界的振舞い
    空間次元無限大で厳密となる動的平均場理論は、フェルミ液体とモット絶縁体をともにコンシステントに記述する理論として、広くモット転移の研究に用いられている。しかし、絶対零度のモット転移点の近傍ではエネルギースケールが非常に小さくなるため、数値的に解を求めることが困難となる。モット転移を記述する解析的理論として、準粒子ピークを関数で近似した線形動的平均場理論がある。1バンドハバード模型に対するモット転移点の解析的な結果は、厳密対角化法などの数値計算の結果と非常によく一致する。この理論を用いて2バンドハバード模型の金属絶縁体転移の相図を求め、モットハバード型と電荷移動型領域を含む金属絶縁体転移の全貌を明らかにした。さらに1バンドハバード模型のモット転移近傍の臨界的振舞いを調べ、準粒子繰り込み因子、圧縮率、電子の二重占有数、局所帯磁率などの物理量を、相互

    researchmap

  • I/N展開法と数値対角化法を相補的に用いた無限大次元の強相関電子系の研究

    1996.4 - 1997.3

    日本学術振興会  科学研究費助成事業  奨励研究

      More details

    Grant type:Competitive

    Grant amount:\1000000 ( Direct Cost: \1000000 )

    銅酸化物高温超伝導体では、CuO_2面内のCuをZnで置換することにより(非磁性不純物)、Tcの減少と同時に、特にアンダードープ領域では、(1)不純物の周囲に局在磁気モーメントが誘起される、(2)s波散乱のunitarity limitを上回る大きな残留抵抗を与える、などの異常な振舞いを示すことが知られている。本研究では、Ud=∞のd-p模型を用いて、dサイトの置換によって不純物の周囲の電子状態がどのように変化するかを調べた。Zn置換の効果は、原子準位をホール描像で、ε^i_o(Zn)>ε_p>ε^i_o(Cu)とする事により考慮した。1/N_δ展開の最低次の近似において、pホール及びslave-bosonの1粒子Green関数に対する自己無撞着方程式を導き、T=0の時この方程式を数値的に解いた。不純物の周囲ではslave-bosonの共鳴準位の束縛エネルギーω^i_oは、pホール数n^i_oのFriedel振動を反映して振動するが、ホールドピング量が小さい時には、さらにω^i_oは不純物の近傍で小さくなる。これはdスピンを持たないZnサイトが周囲のpホ

    researchmap

  • 重い電子系のメタ磁性の理論

    1995.4 - 1996.3

    日本学術振興会  科学研究費助成事業  奨励研究

      More details

    Grant type:Competitive

    Grant amount:\1100000 ( Direct Cost: \1100000 )

    低温まで磁気秩序を示さない重い電子系のCeRu_2Si_2は、磁場HをかけることによりH_M〜7.7Teslaで磁化が急激に増大するメタ磁性的な振舞いを示す。このメタ磁性にともない、様々な物理量がH〜H_Mで急激に変化する。さらに最近、フェルミ面の急激な変化がド・ハ-ス-ファン・アルフェン効果の実験により報告され、注目を集めている。
    この問題を理論的に解明するため、U=∞の格子アンダーソン模型の磁化過程を1/N展開理論により調べた。1/N展開の0次近似におけるスレーブボソンと伝導電子の1粒子グリーン関数を与える自己無撞着積分方程式を数値的に解いた。その結果、絶対零度では、臨界磁場H_Mにおいて磁化Mが折れ曲がり、微分帯磁率dM/dHに飛びが現れることを示した。ここでH_Mは、ゼーマンエネルギーがスレーブボソンの共鳴準位の束縛エネルギーE_0と一致する条件により決められる。H<H_Mでは、フェルミ面はLuttinger総和則によって決まる大きなフェルミ面であるが、H>H_Mではフェルミ

    researchmap

  • 近藤絶縁体の理論

    1993.4 - 1994.3

    日本学術振興会  科学研究費助成事業  奨励研究

      More details

    Grant type:Competitive

    Grant amount:\900000 ( Direct Cost: \900000 )

    最近、Ce_3Bi_4Pt_3に代表される近藤絶縁体と呼ばれる新しい物質群が注目を集めている。本研究では、近藤絶縁体を格子アンダーソン模型を用いて理論的に調べた。本研究代表者はこれまでの研究で、この模型を軌道縮重度Nが大きな極限でもサイト間相関効果が十分に取り込める形に修正して、N→∞の極限で局所拘束条件を満たす厳密な1粒子グリーン関数を与える自己無撞着積分方程式を導き、この方程式を数値的に解くことにより重い電子系の振舞いを全温度領域で統一的に記述した(Y.Ono et al.:J.Phys.Soc.Jpn.60(1991)3475)。この自己無撞着積分方程式を近藤絶縁体を導くパラメータ領域に対して数値的に解くことにより、以下の結果を得た。
    1.伝導電子とf電子の総数がユニットセルあたり2個(一般には偶数)の時、この系は近藤絶縁体として振る舞う。
    2.高温T>E_0では、電気抵抗の対数温度依存性や帯磁率のキュリーワイス則など、近藤効果の特徴を示す。ここで、E_0はスレーブボソンの共鳴準位

    researchmap

  • 強い相関のある電子系の電子状態および超伝導機構に関する理論

    1990.4 - 1991.3

    日本学術振興会  科学研究費助成事業  特別研究員奨励費

      More details

    Grant type:Competitive

    Grant amount:\1000000 ( Direct Cost: \1000000 )

    researchmap

  • 強相関電子系の理論

    1988.4

    科学研究費補助金 

      More details

    Grant type:Competitive

    researchmap

  • 低次元電子系の理論

    1986.4

    科学研究費補助金 

      More details

    Grant type:Competitive

    researchmap

▶ display all

 

Teaching Experience (researchmap)

▶ display all

Teaching Experience

  • 強相関物理学I

    2022
    Institution name:新潟大学

  • 理学基礎演習

    2022
    Institution name:新潟大学

  • Physics TodayI

    2021
    Institution name:新潟大学

  • 固体電子論

    2021
    Institution name:新潟大学

  • 理学スタディ・スキルズ

    2021
    Institution name:新潟大学

  • 現代物理学セミナーB

    2020
    Institution name:新潟大学

  • 統計力学IIB

    2020
    Institution name:新潟大学

  • 現代物理学セミナーA

    2020
    Institution name:新潟大学

  • 統計力学IIA

    2020
    Institution name:新潟大学

  • 物性物理学

    2019
    Institution name:新潟大学

  • 理学スタディ・スキルズ

    2017
    -
    2021
    Institution name:新潟大学

  • 自然科学総論Ⅰ

    2016
    Institution name:新潟大学

  • 物理数学演習II

    2015
    -
    2016
    Institution name:新潟大学

  • 数理物質科学特定研究Ⅱ(物理学)

    2013
    -
    2015
    Institution name:新潟大学

  • 研究発表演習・発表Ⅰ

    2013
    -
    2015
    Institution name:新潟大学

  • 数理物質科学特定研究ⅡA(物理学)

    2013
    -
    2015
    Institution name:新潟大学

  • 数理物質科学特定研究Ⅰ(物理学)

    2013
    -
    2015
    Institution name:新潟大学

  • 数理物質科学特定研究ⅡB(物理学)

    2013
    -
    2015
    Institution name:新潟大学

  • 数理物質科学演習Ⅱ(物理学)

    2013
    -
    2015
    Institution name:新潟大学

  • 研究発表演習・発表Ⅱ

    2013
    -
    2015
    Institution name:新潟大学

  • 数理物質科学演習Ⅰ(物理学)

    2013
    -
    2015
    Institution name:新潟大学

  • 課題探索特講

    2012
    -
    2015
    Institution name:新潟大学

  • 数理物質科学演習Ⅲ(物理学)

    2012
    -
    2015
    Institution name:新潟大学

  • コラボレーション演習

    2012
    -
    2015
    Institution name:新潟大学

  • 数理物質科学特定研究Ⅲ(物理学)

    2012
    -
    2015
    Institution name:新潟大学

  • 研究発表演習・発表Ⅲ

    2012
    -
    2015
    Institution name:新潟大学

  • 統計力学演習I

    2012
    Institution name:新潟大学

  • 論文演習

    2012
    Institution name:新潟大学

  • Physics of Information and Nano Technolo

    2012
    Institution name:新潟大学

  • 物性理論特論

    2012
    Institution name:新潟大学

  • 物性物理学I

    2010
    -
    2017
    Institution name:新潟大学

  • ITおよびナノテクの物理

    2009
    -
    2011
    Institution name:新潟大学

  • 統計力学II

    2008
    Institution name:新潟大学

  • 統計力学演習II

    2008
    Institution name:新潟大学

  • 強相関物理学Ⅰ

    2008
    -
    2020
    Institution name:新潟大学

  • 物性物理学II

    2008
    -
    2016
    Institution name:新潟大学

  • 物理学基礎A I

    2007
    Institution name:新潟大学

  • 固体電子論

    2007
    -
    2021
    Institution name:新潟大学

  • 電磁気学b

    2007
    Institution name:新潟大学

  • 強相関物理学I

    2007
    Institution name:新潟大学

  • 統計力学III

    2007
    Institution name:新潟大学

▶ display all