Faculty Profiles - ISHIZUKA Jun

写真a

ISHIZUKA Jun

Organization

Academic Assembly Institute of Science and Technology SEISAN DESIGN KOUGAKU KEIRETU Assistant Professor
Faculty of Engineering Assistant Professor
Graduate School of Science and Technology Advanced Materials Science and Technology Assistant Professor

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Degree

Ph.D. (Science) ( 2017.3 Niigata University )

Research Areas

Natural Science / Magnetism, superconductivity and strongly correlated systems

Research History (researchmap)

Niigata University Faculty of Engineering Department of Engineering Assistant Professor

2022.4

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Country：Japan

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ETH Zurich Department of Physics Postdoctoral Researcher

2021.4 - 2022.3

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Country：Switzerland

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Kyoto University Graduate School of Science Postdoctoral Researcher

2017.4 - 2021.3

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Country：Japan

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Research History

Niigata University Institute of Science and Technology, Academic Assembly Assistant Professor

2022.4
Niigata University Faculty of Engineering Assistant Professor

2022.4
Niigata University Advanced Materials Science and Technology, Graduate School of Science and Technology Assistant Professor

2022.4

Education

Niigata University Graduate School of Science and Technology Specialized Course Fundamental Sciences

2014.4 - 2017.3

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Country： Japan

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Niigata University Graduate School of Science and Technology Specialized Course Fundamental Sciences

2012.4 - 2014.3

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Country： Japan

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Niigata University Faculty of Science Department of Physics

- 2012.3

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Country： Japan

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Papers

Magnetic edge fields in UTe2 near zero background fields

Yusuke Iguchi, Huiyuan Man, S. M. Thomas, Filip Ronning, Jun Ishizuka, Manfred Sigrist, Priscila F. S. Rosa, Kathryn A. Moler

Physical Review B 2024.12

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Publishing type：Research paper (scientific journal)

DOI： 10.1103/PhysRevB.110.214505

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Correlation-induced Fermi surface evolution and topological crystalline superconductivity in CeRh2As2

Jun Ishizuka, Kosuke Nogaki, Manfred Sigrist, Youichi Yanase

Physical Review B 2024.10

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Publishing type：Research paper (scientific journal)

DOI： 10.1103/PhysRevB.110.L140505

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Coexistence of near EF Flat Band and Van Hove Singularity in a Two-Phase Superconductor Reviewed

Xuezhi Chen, Le Wang, Jun Ishizuka, Renjie Zhang, Kosuke Nogaki, Yiwei Cheng, Fazhi Yang, Zhenhua Chen, Fangyuan Zhu, Zhengtai Liu, Jiawei Mei, Youichi Yanase, Baiqing Lv, Yaobo Huang

Physical Review X 14 ( 2 ) 2024.6

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Authorship：Lead author Publishing type：Research paper (scientific journal) Publisher：American Physical Society (APS)

Quantum many-body systems, particularly, the ones with large near-EF density states, are well known for exhibiting rich phase diagrams as a result of enhanced electron correlations. The recently discovered locally noncentrosymmetric heavy fermion superconductor CeRh2As2 has stimulated extensive attention due to its unusual H−T phase diagram consisting of two-phase superconductivity, antiferromagnetic order, and possible quadrupole-density wave orders. However, the critical near-EF electronic structure remains experimentally elusive. Here, we provide this key information by combining soft-x-ray and vacuum ultraviolet (VUV) angle-resolved-photoemission-spectroscopy measurements and atom-resolved density-functional-theory (DFT)+U calculations. With bulk-sensitive soft x ray, we reveal quasi-2D hole and electron pockets near the EF. On the other hand, under VUV light, the Ce flat bands are resolved with the c−f hybridization persisting up to well above the Kondo temperature. Most importantly, we observe a symmetry-protected fourfold Van Hove singularity (VHS) coexisting with the Ce 4f5/21 flat bands at the X point, which, to the best of our knowledge, has never been reported before. Such a rare coexistence is expected to lead to a large density of states at the zone edge, a large upper critical field of the odd-parity phase, as well as spin and/or charge instabilities with a vector of (1/2, 1/2, 0). Uniquely, it will also result in a new type of f-VHS hybridization that alters the order and fine electronic structure of the VHS and flat bands. Our findings provide not only key insights into the nature of multiple phases in CeRh2As2 but also open up new prospects for exploring the novelties of many-body systems with f-VHS hybridization.

Published by the American Physical Society 2024

DOI： 10.1103/physrevx.14.021048

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Other Link： http://harvest.aps.org/v2/journals/articles/10.1103/PhysRevX.14.021048/fulltext
Magnetization Control of Zero‐Field Intrinsic Superconducting Diode Effect Reviewed International journal

Hideki Narita, Jun Ishizuka, Daisuke Kan, Yuichi Shimakawa, Youichi Yanase, Teruo Ono

Advanced Materials e2304083 2023.8

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Language：English Publishing type：Research paper (scientific journal)

The superconducting diode effect (SDE), which causes a superconducting state in one direction and a normal-conducting state in another, has significant potential for developing ultralow power consumption circuits and non-volatile memory. However, the practical control of the SDE necessities the precise tuning of current, temperature, magnetic field, or magnetism. Therefore, the mechanisms of the SDE must be understood to develop novel materials and devices capable of realizing the SDE under more controlled and robust conditions. This study demonstrates an intrinsic zero-field SDE with an efficiency of up to 40% in Fe/Pt-inserted non-centrosymmetric Nb/V/Ta superconducting artificial superlattices. The polarity and magnitude of the zero-field SDE are controllable by the direction of magnetization, indicating that the effective exchange field acts on Cooper pairs. Furthermore, the first-principles calculation indicates that the SDE can be enhanced by an asymmetric configuration of proximity induced magnetic moments in superconducting layers, which induces a magnetic toroidal moment. This study has important implications regarding the development of novel materials and devices that can effectively control the SDE. Moreover, the magnetization control of the SDE is expected to aid in the designing of superconducting quantum devices and establishing a material platform for topological superconductors.

DOI： 10.1002/adma.202304083

PubMed

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de Haas–van Alphen Oscillations for the Field Along c-axis in UTe2 Reviewed

Dai Aoki, Ilya Sheikin, Alix McCollam, Jun Ishizuka, Youichi Yanase, Gerard Lapertot, Jacques Flouquet, Georg Knebel

Journal of the Physical Society of Japan 2023.6

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Publishing type：Research paper (scientific journal)

DOI： 10.7566/JPSJ.92.065002

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

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 91 ( 8 ) 2022.8

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

DOI： 10.7566/JPSJ.91.083704

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

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 2022.6

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Publishing type：Research paper (scientific journal) Publisher：Springer Science and Business Media LLC

DOI： 10.1038/s41565-022-01159-4

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Other Link： https://www.nature.com/articles/s41565-022-01159-4
Superconductivity in monolayer FeSe enhanced by quantum geometry Reviewed

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

Physical Review Research 4 ( 2 ) 2022.6

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Publishing type：Research paper (scientific journal) Publisher：American Physical Society (APS)

DOI： 10.1103/PhysRevResearch.4.023232

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Other Link： http://harvest.aps.org/v2/journals/articles/10.1103/PhysRevResearch.4.023232/fulltext
Topological crystalline superconductivity in locally noncentrosymmetric CeRh2As2 Reviewed

Kosuke Nogaki, Akito Daido, Jun Ishizuka, Youichi Yanase

Physical Review Research 3 ( 3 ) 2021.9

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Publishing type：Research paper (scientific journal) Publisher：American Physical Society (APS)

DOI： 10.1103/PhysRevResearch.3.L032071

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Other Link： http://harvest.aps.org/v2/journals/articles/10.1103/PhysRevResearch.3.L032071/fulltext
Magnetic Properties under Pressure in Novel Spin-Triplet Superconductor UTe2 Reviewed

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 2021.7

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Language：English Publishing type：Research paper (scientific journal)

DOI： 10.7566/jpsj.90.073703

Web of Science

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

Taisei Kitamura, Jun Ishizuka, Akito Daido, Youichi Yanase

Physical Review B 103 ( 24 ) 2021.6

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Publishing type：Research paper (scientific journal) Publisher：American Physical Society (APS)

DOI： 10.1103/PhysRevB.103.245114

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Other Link： http://harvest.aps.org/v2/journals/articles/10.1103/PhysRevB.103.245114/fulltext
Periodic Anderson model for magnetism and superconductivity in UTe 2 Reviewed

Ishizuka, Jun, Yanase, Youichi

Physical Review B 103 ( 9 ) 094504 - 094504 2021.3

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Authorship：Lead author,　Corresponding author Publishing type：Research paper (scientific journal) Publisher：American Physical Society

DOI： 10.1103/physrevb.103.094504

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Other Link： http://harvest.aps.org/v2/journals/articles/10.1103/PhysRevB.103.094504/fulltext
Observation of superconducting diode effect Reviewed

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

Nature 584 ( 7821 ) 373 - 376 2020.8

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Publishing type：Research paper (scientific journal) Publisher：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 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

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

DOI： 10.7566/jpscp.30.011043

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Insulator-Metal Transition and Topological Superconductivity in UTe 2 from a First-Principles Calculation Reviewed

Ishizuka, Jun, Sumita, Shuntaro, Daido, Akito, Yanase, Youichi

Physical Review Letters 123 ( 21 ) 217001 - 217001 2019.11

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Authorship：Lead author,　Corresponding author Publishing type：Research paper (scientific journal) Publisher：American Physical Society

DOI： 10.1103/physrevlett.123.217001

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Other Link： http://harvest.aps.org/v2/journals/articles/10.1103/PhysRevLett.123.217001/fulltext
LDA+U study of electronic state and superconductivity in UTe2

Ishizuka Jun, Sumita S., Akito D., Yanase Youichi

Meeting Abstracts of the Physical Society of Japan 74.2 1867 - 1867 2019

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Language：Japanese Publisher：The Physical Society of Japan

DOI： 10.11316/jpsgaiyo.74.2.0_1867

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

Ishizuka, Jun, Yanase, Youichi

Physical Review B 98 ( 22 ) 224510 - 224510 2018.12

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Authorship：Lead author,　Corresponding author Publishing type：Research paper (scientific journal) Publisher：APS

DOI： 10.1103/physrevb.98.224510

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Other Link： http://harvest.aps.org/v2/journals/articles/10.1103/PhysRevB.98.224510/fulltext
Fermi surface, pressure-induced antiferromagnetic order, and superconductivity in FeSe Reviewed

Ishizuka, Jun, Yamada, Takemi, Yanagi, Yuki, O}no, Yoshiaki

journal of the physical society of japan 87 ( 1 ) 014705 - 014705 2018.1

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Authorship：Lead author,　Corresponding author Publishing type：Research paper (scientific journal) Publisher：The Physical Society of Japan

DOI： 10.7566/jpsj.87.014705

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Electronic structure and superconducting gap structure in UPt3 based on the first-principles band calculation

Ishizuka Jun, Sumita Shuntaro, Yanase Youichi

Meeting Abstracts of the Physical Society of Japan 73.2 1738 - 1738 2018

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Language：Japanese Publisher：The Physical Society of Japan

DOI： 10.11316/jpsgaiyo.73.2.0_1738

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Theory of magnetic multipole fluctuation and superconductivity in non-symmorphic crystalline Sr2IrO4

Ishizuka Jun, Sumita Shuntaro, Yanase Youichi

Meeting Abstracts of the Physical Society of Japan 73.1 2034 - 2034 2018

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Language：Japanese Publisher：The Physical Society of Japan

DOI： 10.11316/jpsgaiyo.73.1.0_2034

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Hole-s± State Induced by Coexisting Ferro- and Antiferromagnetic and Antiferro-orbital Fluctuations in Iron Pnictides Reviewed

Jun Ishizuka, Takemi Yamada, Yuki Yanagi, Yoshiaki Ōno

Journal of the Physical Society of Japan 85 ( 11 ) 114709 - 114709 2016.11

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Authorship：Lead author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：Physical Society of Japan

DOI： 10.7566/jpsj.85.114709

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

Jun Ishizuka, Takemi Yamada, Yoshiaki Ōno

Journal of Physics: Conference Series 592 ( 1 ) 012077 - 012077 2015.3

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Authorship：Lead author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：IOP Publishing

DOI： 10.1088/1742-6596/592/1/012077

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Other Link： 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 Five-Orbital Hubbard Model for Iron Pnictides Reviewed

Jun Ishizuka, Takemi Yamada, Yuki Yanagi, Yoshiaki Ōno

Proceedings of the International Conference on Strongly Correlated Electron Systems (SCES2013) 3 15020 - 1-015020-6 2014.6

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Authorship：Lead author,　Corresponding author Language：English Publishing type：Research paper (international conference proceedings) Publisher：Journal of the Physical Society of Japan

DOI： 10.7566/jpscp.3.015020

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

Takemi Yamada, Jun Ishizuka, Yoshiaki Ōno

Journal of the Physical Society of Japan 83 ( 4 ) 043704 - 043704 2014.4

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

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 Reviewed

Takemi Yamada, Jun Ishizuka, Yoshiaki Ōno

Journal of the Physical Society of Japan 83 ( 4 ) 044711 - 044711 2014.4

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Language：English Publishing type：Research paper (scientific journal) Publisher：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, <italic>U</italic>and <italic>U</italic>′, increase with <italic>U</italic>= <italic>U</italic>′, both the local spin and orbital susceptibilities, χsand χo, increase with χs= χoin the absence of the Hund's rule coupling <italic>J</italic>and the electron–phonon coupling <italic>g</italic>. In the presence of <italic>J</italic>and <italic>g</italic>, there are distinct two regimes: for <inline-formula><tex-math version="MathJax"><![CDATA[\(J \gtrsim 2g^{2}/\omega _{0}\)]]></tex-math></inline-formula>with the phonon frequency ω0, χsis enhanced relative to χoand shows a divergence at <italic>J</italic>= <italic>J</italic>cabove which the system becomes Mott insulator, while for <inline-formula><tex-math version="MathJax"><![CDATA[\(J \lesssim 2g^{2}/\omega _{0}\)]]></tex-math></inline-formula>, χois enhanced relative to χsand shows a divergence at <italic>g</italic>= <italic>g</italic>cabove 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±- 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 Ōno

Journal of the Physical Society of Japan 82 ( 12 ) 123712 - 123712 2013.12

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Authorship：Lead author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：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

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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 2020.11

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J-GLOBAL

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

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

Meeting Abstracts of the Physical Society of Japan 74.2 1672 - 1672 2019

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Language：Japanese Publisher：The Physical Society of Japan

DOI： 10.11316/jpsgaiyo.74.2.0_1672

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Teaching Experience

先端科学技術総論

2025
Institution name：新潟大学
物理数学

2024
Institution name：新潟大学
エンジニアのためのデータサイエンス入門(化学材料分野)

2024
Institution name：新潟大学
論文輪講

2024
Institution name：新潟大学
技術英語

2024
Institution name：新潟大学
データサイエンス概説演習

2023
Institution name：新潟大学
工学リテラシー入門(化学材料分野)

2023
Institution name：新潟大学
材料科学概論

2023
Institution name：新潟大学
データサイエンス実践 C

2023
Institution name：新潟大学
学問の扉知と方法の最前線

2023
Institution name：新潟大学
材料科学実験I

2022
Institution name：新潟大学
材料科学実験I

2022
Institution name：新潟大学
卒業研究

2022
Institution name：新潟大学
卒業研修

2022
Institution name：新潟大学
技術英語I

2022

-

2024
Institution name：新潟大学
論文輪講II

2022

-

2024
Institution name：新潟大学
論文輪講I

2022

-

2024
Institution name：新潟大学
技術英語II

2022

-

2024
Institution name：新潟大学

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