2022/12/10 更新

写真a

イシヅカ ジユン
石塚 淳
ISHIZUKA Jun
所属
教育研究院 自然科学系 生産デザイン工学系列 助教
工学部 助教
自然科学研究科 材料生産システム専攻 助教
職名
助教
外部リンク

学位

  • 博士(理学) ( 2017年3月   新潟大学 )

研究分野

  • 自然科学一般 / 磁性、超伝導、強相関系

経歴(researchmap)

  • 新潟大学   工学部 工学科 材料科学プログラム   助教

    2022年4月 - 現在

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    国名:日本国

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  • ETH Zurich   Department of Physics   Postdoctoral Researcher

    2021年4月 - 2022年3月

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    国名:スイス連邦

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  • 京都大学   大学院理学研究科   特定研究員

    2017年4月 - 2021年3月

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    国名:日本国

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経歴

  • 新潟大学   教育研究院 自然科学系 生産デザイン工学系列   助教

    2022年4月 - 現在

  • 新潟大学   工学部   助教

    2022年4月 - 現在

  • 新潟大学   自然科学研究科 材料生産システム専攻   助教

    2022年4月 - 現在

学歴

  • 新潟大学   大学院自然科学研究科   数理物質科学専攻

    2014年4月 - 2017年3月

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    国名: 日本国

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  • 新潟大学   大学院自然科学研究科   数理物質科学専攻

    2012年4月 - 2014年3月

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    国名: 日本国

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  • 新潟大学   理学部   物理学科

    - 2012年3月

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    国名: 日本国

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論文

  • First Observation of the de Haas–van Alphen Effect and Fermi Surfaces in the Unconventional Superconductor UTe2 査読

    Dai Aoki, Hironori Sakai, Petr Opletal, Yoshifumi Tokiwa, Jun Ishizuka, Youichi Yanase, Hisatomo Harima, Ai Nakamura, Dexin Li, Yoshiya Homma, Yusei Shimizu, Georg Knebel, Jacques Flouquet, Yoshinori Haga

    Journal of the Physical Society of Japan   2022年8月

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    掲載種別:研究論文(学術雑誌)  

    DOI: 10.7566/JPSJ.91.083704

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  • Field-free superconducting diode effect in noncentrosymmetric superconductor/ferromagnet multilayers 査読

    Hideki Narita, Jun Ishizuka, Ryo Kawarazaki, Daisuke Kan, Yoichi Shiota, Takahiro Moriyama, Yuichi Shimakawa, Alexey V. Ognev, Alexander S. Samardak, Youichi Yanase, Teruo Ono

    Nature Nanotechnology   2022年6月

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    掲載種別:研究論文(学術雑誌)   出版者・発行元:Springer Science and Business Media LLC  

    DOI: 10.1038/s41565-022-01159-4

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    その他リンク: https://www.nature.com/articles/s41565-022-01159-4

  • Superconductivity in monolayer FeSe enhanced by quantum geometry 査読

    Taisei Kitamura, Tatsuya Yamashita, Jun Ishizuka, Akito Daido, Youichi Yanase

    Physical Review Research   2022年6月

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    掲載種別:研究論文(学術雑誌)  

    DOI: 10.1103/PhysRevResearch.4.023232

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  • Topological crystalline superconductivity in locally noncentrosymmetric CeRh2As2 査読

    Kosuke Nogaki, Akito Daido, Jun Ishizuka, Youichi Yanase

    Physical Review Research   3 ( 3 )   2021年9月

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    掲載種別:研究論文(学術雑誌)   出版者・発行元:American Physical Society (APS)  

    DOI: 10.1103/physrevresearch.3.l032071

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    その他リンク: http://harvest.aps.org/v2/journals/articles/10.1103/PhysRevResearch.3.L032071/fulltext

  • Magnetic Properties under Pressure in Novel Spin-Triplet Superconductor UTe2 査読

    Dexin Li, Ai Nakamura, Fuminori Honda, Yoshiki J. Sato, Yoshiya Homma, Yusei Shimizu, Jun Ishizuka, Youichi Yanase, Georg Knebel, Jacques Flouquet, Dai Aoki

    Journal of the Physical Society of Japan   90 ( 7 )   073703 - 073703   2021年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Physical Society of Japan  

    We report the magnetic susceptibility and the magnetization under pressures up to 1.7 GPa above the critical pressure, P-c similar to 1.5 GPa, for H parallel to a, b, and c-axes in the novel spin triplet superconductor UTe2. The anisotropic magnetic susceptibility at low pressure with the easy magnetization a-axis changes to the quasi-isotropic behavior at high pressure, revealing a rapid suppression of the susceptibility for a-axis, and a gradual increase of the susceptibility for the b-axis. At 1.7 GPa above P-c, magnetic anomalies are detected at T-MO similar to 3K and T-WMO similar to 10 K. The former anomaly corresponds to long-range magnetic order, most likely antiferromagnetism, while the latter shows a broad anomaly, which is probably due to the development of short range order. The unusual decrease and increase of the susceptibility below T-WMO for H parallel to a and b-axes, respectively, indicate the complex magnetic properties at low temperatures above P-c. This is related to the interplay between multiple fluctuations dominated by antiferromagnetism, ferromagnetism, valence and Fermi surface instabilities.

    DOI: 10.7566/jpsj.90.073703

    Web of Science

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  • Thermodynamic electric quadrupole moments of nematic phases from first-principles calculations 査読

    Taisei Kitamura, Jun Ishizuka, Akito Daido, Youichi Yanase

    Physical Review B   103 ( 24 )   2021年6月

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    掲載種別:研究論文(学術雑誌)   出版者・発行元:American Physical Society (APS)  

    DOI: 10.1103/physrevb.103.245114

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    その他リンク: http://harvest.aps.org/v2/journals/articles/10.1103/PhysRevB.103.245114/fulltext

  • Periodic Anderson model for magnetism and superconductivity in UTe2 査読

    Jun Ishizuka, Youichi Yanase

    Physical Review B   103 ( 9 )   2021年3月

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    担当区分:筆頭著者   掲載種別:研究論文(学術雑誌)   出版者・発行元:American Physical Society (APS)  

    DOI: 10.1103/physrevb.103.094504

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    その他リンク: http://harvest.aps.org/v2/journals/articles/10.1103/PhysRevB.103.094504/fulltext

  • Observation of superconducting diode effect 査読

    Fuyuki Ando, Yuta Miyasaka, Tian Li, Jun Ishizuka, Tomonori Arakawa, Yoichi Shiota, Takahiro Moriyama, Youichi Yanase, Teruo Ono

    Nature   584 ( 7821 )   373 - 376   2020年8月

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    掲載種別:研究論文(学術雑誌)   出版者・発行元:Springer Science and Business Media {LLC}  

    DOI: 10.1038/s41586-020-2590-4

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

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

    Proceedings of the International Conference on Strongly Correlated Electron Systems (SCES2019)   2020年3月

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    掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:Journal of the Physical Society of Japan  

    DOI: 10.7566/jpscp.30.011043

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  • Insulator-Metal Transition and Topological Superconductivity in UTe2 査読

    Jun Ishizuka, Shuntaro Sumita, Akito Daido, Youichi Yanase

    Physical Review Letters   123 ( 21 )   2019年11月

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    担当区分:筆頭著者   掲載種別:研究論文(学術雑誌)   出版者・発行元:American Physical Society (APS)  

    DOI: 10.1103/physrevlett.123.217001

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    その他リンク: http://harvest.aps.org/v2/journals/articles/10.1103/PhysRevLett.123.217001/fulltext

  • LDA+UによるUTe<sub>2</sub>の電子状態と超伝導

    石塚 淳, 角田 峻太郎, 大同 暁人, 柳瀬 陽一

    日本物理学会講演概要集   74.2   1867 - 1867   2019年

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    記述言語:日本語   出版者・発行元:一般社団法人 日本物理学会  

    DOI: 10.11316/jpsgaiyo.74.2.0_1867

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  • Odd-parity multipole fluctuation and unconventional superconductivity in locally noncentrosymmetric crystal 査読

    Jun Ishizuka, Youichi Yanase

    Physical Review B   98 ( 22 )   2018年12月

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    担当区分:筆頭著者   掲載種別:研究論文(学術雑誌)   出版者・発行元:American Physical Society (APS)  

    DOI: 10.1103/physrevb.98.224510

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    その他リンク: http://harvest.aps.org/v2/journals/articles/10.1103/PhysRevB.98.224510/fulltext

  • Fermi Surface, Pressure-Induced Antiferromagnetic Order, and Superconductivity in FeSe 査読

    Jun Ishizuka, Takemi Yamada, Yuki Yanagi, Yoshiaki Ōno

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

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    担当区分:筆頭著者   掲載種別:研究論文(学術雑誌)   出版者・発行元:Physical Society of Japan  

    DOI: 10.7566/jpsj.87.014705

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  • 非共型結晶Sr<sub>2</sub>IrO<sub>4</sub>における磁気多極子揺らぎと超伝導の理論

    石塚 淳, 角田 峻太郎, 柳瀬 陽一

    日本物理学会講演概要集   73.1   2034 - 2034   2018年

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    記述言語:日本語   出版者・発行元:一般社団法人 日本物理学会  

    DOI: 10.11316/jpsgaiyo.73.1.0_2034

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  • 第一原理計算によるUPt<sub>3</sub>の電子状態と超伝導ギャップ構造

    石塚 淳, 角田 峻太郎, 柳瀬 陽一

    日本物理学会講演概要集   73.2   1738 - 1738   2018年

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    記述言語:日本語   出版者・発行元:一般社団法人 日本物理学会  

    DOI: 10.11316/jpsgaiyo.73.2.0_1738

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  • Hole-s_± State Induced by Coexisting Ferro- and Aniferromagnetic and Aniferro-orbital Fluctuations in Iron Pnictides 査読

    Ishizuka Jun, Yamada Takemi, Yanagi Yuki, Ono Yoshiaki

    Journal of the Physical Society of Japan   85 ( 11 )   114709 - 114709   2016年11月

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    担当区分:筆頭著者   記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:The Physical Society of Japan  

    The five-orbital Hubbard model for iron-based superconductors is investigated by 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 (AMF) and the antiferro-orbital (AFO) fluctuations are comparably enhanced, the orbital dependence of the vertex function becomes 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 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 a specific compound LiFeAs.

    DOI: 10.7566/jpsj.85.114709

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

    Ishizuka Jun, Yamada Takemi, Ono Yoshiaki

    Journal of Physics: Conference Series   592 ( 1 )   012077 - 012077   2015年3月

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    担当区分:筆頭著者   記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:IOP Publishing  

    The five-orbital Hubbard model for iron pnictides is investigated by using the dynamical meanfield 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

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    その他リンク: http://stacks.iop.org/1742-6596/592/i=1/a=012077?key=crossref.2245a071b21865554ab6a5612ddb1599

  • Dynamical mean-field study on the superconductivity mediated by spin and orbital fluctuations in the 5-orbital Hubbard model for iron pnictides 査読

    Ishizuka Jun, Yamada Takemi, Yanagi Yuki, Ono Yoshiaki

    JPS Conference Proceedings   3   15020 - 1-015020-6   2014年6月

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    担当区分:筆頭著者   記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:The Physical Society of Japan  

    We investigate the electronic state and the superconductivity in the 5-orbital Hubbard model for iron pnictides by using the dynamical mean-field theory together with the linearized Eliashberg equation. The renormalization factor exhibits a significant orbital dependence resulting in the band-dependence of the mass enhancement. The critical interactions towards the magnetic, orbital and superconducting instabilities are calculated and found to be suppressed as compared to the corresponding RPA results due to the correlation effects. Remarkably, the s_<++>-pairing phase due to the orbital fluctuation is expanded as compared to the RPA result, while the s_±-pairing phase due to the magnetic fluctuation is largely reduced.

    DOI: 10.7566/jpscp.3.015020

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  • A High-T_c Mechanism of Iron Pnictide Superconductivity due to Cooperation of Ferro-orbital and Antiferromagnetic Fluctuations 査読

    Yamada Takemi, Ishizuka Jun, Ono Yoshiaki

    Journal of the Physical Society of Japan   83 ( 4 )   043704 - 043704   2014年4月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:The Physical Society of 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 ~ Q_<AF> while the FO does the attractive one for q ~ 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

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

    Yamada Takemi, Ishizuka Jun, Ono Yoshiaki

    Journal of the Physical Society of Japan   83 ( 4 )   044711 - 044711   2014年4月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:The Physical Society of 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, χ_s and χ_o, increase with χ_s = χ_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 >__~ 2g^2 /ω_0 with the phonon frequency ω_0, χ_s is enhanced relative to χ_o and shows a divergence at J = J_c above which the system becomes Mott insulator, while for J <__~ 2g^2/ω_0, χ_o is enhanced relative to χ_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

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  • Local Correlation Effects on the s_{\pm}- and s_{++}-Wave Superconductivities Mediated by Magnetic and Orbital Fluctuations in the Five-Orbital Hubbard Model for Iron Pnictides 査読

    Ishizuka Jun, Yamada Takemi, Yanagi Yuki, Ōno Yoshiaki

    J Phys Soc Jpn   82 ( 12 )   123712 - 123712   2013年12月

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    担当区分:筆頭著者   記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:The Physical Society of 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_{\pm}-pairing phase due to the magnetic fluctuation is reduced.

    DOI: 10.7566/jpsj.82.123712

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MISC

  • 強磁性近傍のトポロジカル超伝導体――UTe2とUCoGeの理論予測

    石塚 淳, 大同 暁人, 栁瀬 陽一

    日本物理学会誌   76 ( 5 )   289 - 294   2021年

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  • 奇パリティ多極子相の分類学と電磁応答・超伝導

    渡邉 光, 柳瀬 陽一, 石塚 淳, 金杉 翔太, 大同 暁人, 角田 峻太郎, 下出 敦夫, 塩見 雄毅

    固体物理   55 ( 11 )   535 - 549   2020年11月

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担当経験のある授業科目

  • 技術英語II

    2022年
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    現在
    機関名:新潟大学

  • 技術英語I

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    機関名:新潟大学

  • 材料科学実験I

    2022年
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    機関名:新潟大学

  • 材料科学実験I

    2022年
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    現在
    機関名:新潟大学

  • 卒業研究

    2022年
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    現在
    機関名:新潟大学

  • 卒業研修

    2022年
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    現在
    機関名:新潟大学

  • 論文輪講I

    2022年
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    現在
    機関名:新潟大学

  • 論文輪講II

    2022年
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    現在
    機関名:新潟大学

▶ 全件表示