時間および空間反転対称性を破る奇パリティ・アナポール秩序の解明

• Project/Area Number: 21H04443
• Research Category: Grant-in-Aid for Scientific Research (A)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Medium-sized Section 13:Condensed matter physics and related fields
• Research Institution: Okayama University
• Principal Investigator: 笠原 成 岡山大学, 異分野基礎科学研究所, 教授 (10425556)
• Project Period (FY): 2021-04-05 – 2025-03-31
• Project Status: Granted (Fiscal Year 2024)
• Budget Amount: ¥43,290,000 (Direct Cost: ¥33,300,000、Indirect Cost: ¥9,990,000); Fiscal Year 2024: ¥3,510,000 (Direct Cost: ¥2,700,000、Indirect Cost: ¥810,000); Fiscal Year 2023: ¥6,500,000 (Direct Cost: ¥5,000,000、Indirect Cost: ¥1,500,000); Fiscal Year 2022: ¥7,020,000 (Direct Cost: ¥5,400,000、Indirect Cost: ¥1,620,000); Fiscal Year 2021: ¥26,260,000 (Direct Cost: ¥20,200,000、Indirect Cost: ¥6,060,000)
• Keywords: 奇パリティ秩序 / 時間反転対称性の破れ / 強相関電子系 / エキゾチック凝縮相 / アナポール / 熱輸送測定 / 磁気トルク / 圧力下比熱測定 / 新奇凝縮状態 / 磁気トルク測定 / ネマティック秩序 / ネマティック量子臨界点 / FFLO超伝導 / 量子液晶 / イリジウム酸化物 / 銅酸化物

Outline of Research at the Start

凝縮系物理学において、時間および空間反転対称性を自発的に破る奇パリティのアナポール秩序は極めて稀有な新奇量子相である。本研究では、5dイリジウム酸化物Sr2IrO4を母物質としたスピン・軌道モット絶縁体近傍での電子状態に焦点をあて、強相関電子系が創発する奇パリティ・アナポール秩序の探索と解明に取り組む。回転対称性の破れを超高感度で検出可能な面内磁気トルク測定、磁気カイラリティに敏感な熱ホール効果測定を駆使することで、アナポール秩序の有無を検証し、これをもたらす軌道ループ電流のパターンを特定することで、量子多体系が示す新奇量子状態の基礎物理構築に臨む。

Outline of Annual Research Achievements

電荷・スピン・軌道といった複合自由度が絡み合う強相関電子系物質においては、多種多様なエキゾチック凝縮相が創発される。本研究では、そのようなエキゾチック凝縮相の探索と解明を主眼におき、時間および空間反転対称性の両者を自発的に破る奇パリティ秩序 (=アナポール秩序)などの研究を進めている。当該年度では、前年度に引き続き、鉄系超伝導体FeSe1-xSxにおける回転対称性の破れたネマティック相とその量子臨界現象に関する物理を強磁場輸送現象測定などを通じて調べ、その量子臨界性についての報告を行った。また、新研究室において、3He冷凍機を用いた長時間緩和法を用いた精密比熱測定の立ち上げに取り組み、これと並行して前年度に引き続き、熱輸送測定システムの開発取り組んだ。

Current Status of Research Progress

2: Research has progressed on the whole more than it was originally planned.

Reason

前年度は新型コロナウィルスの影響により、実験装置開発において世界的な部材・人材不足が発生したが、3He装置が納入されるなど、一部の極低温実験が可能な環境が整ってきた。これにより長時間緩和法による精密比熱測定を立ち上げることができ、現在、鉄系超伝導体FeSe1-xSxをはじめとしたエキゾチック量子相の開拓が進んできている。このことからおおむね順調であると判断する。

Strategy for Future Research Activity

新型コロナの影響による装置の納入遅れによって、研究指針は当初計画と異なる方向に進める必要が生じたが、鉄系超伝導体FeSe1-xSxのネマティック秩序とその量子臨界点に関する物理や、各種のエキゾチック凝縮相に関する研究を進めることができている。このことから、当初の主眼であるアナポール秩序に限らず、様々な凝縮相に関する研究を進めていく。

Research Products

• [Int'l Joint Research] Bristol University(英国)
• [Int'l Joint Research] Radboud University(オランダ)
• [Int'l Joint Research] Bristol University(英国)
• [Int'l Joint Research] Radboud University(オランダ)
• [Int'l Joint Research] Paul Scherrer Institute(スイス)
• [Int'l Joint Research] Brookhaven National Laboratory/Massachusetts Institute of Technology/University of Michigan(米国)
• [Journal Article] Enhanced Superconducting Pairing Strength near a Pure Nematic Quantum Critical Point (2023)
  • Author(s): Mukasa Kiyotaka、Ishida Kousuke、Imajo Shusaku、Qiu Mingwei、Saito Mikihiko、Matsuura Kohei、Sugimura Yuichi、Liu Supeng、Uezono Yu、Otsuka Takumi、Culo Matija、Kasahara Shigeru、Matsua Yuji、Hussey Nigel E.、Watanabe Takao、Kindo Koichi、Shibauchi Takasada
  • Journal Title: Physical Review X Volume: 13 Issue: 1 Pages: 011032-011032
  • DOI: 10.1103/physrevx.13.011032
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Transport evidence for decoupled nematic and magnetic criticality in iron chalcogenides (2022)
  • Author(s): Ayres Jake、Culo Matija、Buhot Jonathan、Bernath Bence、Kasahara Shigeru、Matsuda Yuji、Shibauchi Takasada、Carrington Antony、Friedemann Sven、Hussey Nigel E.
  • Journal Title: Communications Physics Volume: 5 Issue: 1 Pages: 100-100
  • DOI: 10.1038/s42005-022-00873-8
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Resistivity and thermal conductivity of an organic insulator β'-EtMe3Sb[Pd(dmit)2]2 (2022)
  • Author(s): Yamashita Minoru、Sato Yuki、Kasahara Yuichi、Kasahara Shigeru、Shibauchi Takasada、Matsuda Yuji
  • Journal Title: Scientific Reports Volume: 12 Issue: 1 Pages: 9187-9187
  • DOI: 10.1038/s41598-022-13155-8
  • Peer Reviewed / Open Access
• [Journal Article] Quantized and unquantized thermal Hall conductance of the Kitaev spin liquid candidate α-RuCl3 (2022)
  • Author(s): Kasahara Y.、Suetsugu S.、Asaba T.、Kasahara S.、Shibauchi T.、Kurita N.、Tanaka H.、Matsuda Y.
  • Journal Title: Physical Review B Volume: 106 Issue: 6
  • DOI: 10.1103/physrevb.106.l060410
  • Peer Reviewed / Open Access
• [Journal Article] スピン軌道モット絶縁体Sr2Ir1-xRhxO4におけるアナポール秩序 (2022)
  • Author(s): 村山陽奈子，笠原 成，松田祐司
  • Journal Title: 固体物理 Volume: 12 Pages: 821-830
  • Peer Reviewed
• [Journal Article] Intrinsic suppression of the topological thermal Hall effect in an exactly solvable quantum magnet (2022)
  • Author(s): S. Suetsugu, T. Yokoi, K. Totsuka, T. Ono, I. Tanaka, S. Kasahara, Y. Kasahara, Z. Chengchao, H. Kageyama, and Y. Matsuda
  • Journal Title: Physical Review B Volume: 105 Issue: 2 Pages: 024415-024415
  • DOI: 10.1103/physrevb.105.024415
  • Peer Reviewed
• [Journal Article] Charge-neutral fermions and magnetic field-driven instability in insulating YbIr3Si7 (2022)
  • Author(s): Sato Y.、Suetsugu S.、Tominaga T.、Kasahara Y.、Kasahara S.、Kobayashi T.、Kitagawa S.、Ishida K.、Peters R.、Shibauchi T.、Nevidomskyy A. H.、Qian L.、Morosan E.、Matsuda Y.
  • Journal Title: Nature Communications Volume: 13 Issue: 1 Pages: 394-394
  • DOI: 10.1038/s41467-021-27541-9
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Putative Hall response of the strange metal component in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>Fe</mml:mi><mml:msub><mml:mi>Se</mml:mi><mml:mrow><mml:mn>1</mml:mn><mml:mo>?</mml:mo><mml:mi>x</mml:mi></mml:mrow></mml:msub><mml:msub><mml:mi mathvariant="normal">S</mml:mi><mml:mi>x</mml:mi></mml:msub></mml:mrow></mml:math> (2021)
  • Author(s): Culo M.、Berben M.、Hsu Y.-T.、Ayres J.、Hinlopen R. D. H.、Kasahara S.、Matsuda Y.、Shibauchi T.、Hussey N. E.
  • Journal Title: Physical Review Research Volume: 3 Issue: 2 Pages: 023069-023069
  • DOI: 10.1103/physrevresearch.3.023069
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Quadrupolar charge dynamics in the nonmagnetic FeSe1-xSx superconductors (2021)
  • Author(s): Zhang Weilu、Wu Shangfei、Kasahara Shigeru、Shibauchi Takasada、Matsuda Yuji、Blumberg Girsh
  • Journal Title: Proceedings of the National Academy of Sciences Volume: 118 Issue: 20
  • DOI: 10.1073/pnas.2020585118
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Topological surface conduction in Kondo insulator YbB₁₂ (2021)
  • Author(s): Sato Y、Xiang Z、Kasahara Y、Kasahara S、Chen L、Tinsman C、Iga F、Singleton J、Nair N L、Maksimovic N、Analytis J G、Li Lu、Matsuda Y
  • Journal Title: Journal of Physics D: Applied Physics Volume: 54 Issue: 40 Pages: 404002-404002
  • DOI: 10.1088/1361-6463/ac10d9
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Description of Resonant Inelastic X-Ray Scattering in Correlated Metals (2021)
  • Author(s): Gilmore Keith、Pelliciari Jonathan、Huang Yaobo、Kas Joshua J.、Dantz Marcus、Strocov Vladimir N.、Kasahara Shigeru、Matsuda Yuji、Das Tanmoy、Shibauchi Takasada、Schmitt Thorsten
  • Journal Title: Physical Review X Volume: 11 Issue: 3 Pages: 031013-031013
  • DOI: 10.1103/physrevx.11.031013
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Half-integer quantized anomalous thermal Hall effect in the Kitaev material candidate α-RuCl ₃ (2021)
  • Author(s): Yokoi T.、Ma S.、Kasahara Y.、Kasahara S.、Shibauchi T.、Kurita N.、Tanaka H.、Nasu J.、Motome Y.、Hickey C.、Trebst S.、Matsuda Y.
  • Journal Title: Science Volume: 373 Issue: 6554 Pages: 568-572
  • DOI: 10.1126/science.aay5551
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Observation of a superconducting state of a topological superconductor candidate, FeTe_0.6Se_0.4, equipping ferromagnetic electrodes with perpendicular magnetic anisotropy (2021)
  • Author(s): Ohnishi Kosuke、Gupta Sachin、Kasahara Shigeru、Kasahara Yuichi、Matsuda Yuji、Shigematsu Ei、Ohshima Ryo、Ando Yuichiro、Shiraishi Masashi
  • Journal Title: Applied Physics Express Volume: 14 Issue: 9 Pages: 093002-093002
  • DOI: 10.35848/1882-0786/ac1ca4
  • Peer Reviewed / Open Access
• [Journal Article] Pressure-Induced Reconstitution of Fermi Surfaces and Spin Fluctuations in S-Substituted FeSe (2021)
  • Author(s): T. Kuwayama, K. Matsuura, J. Gouchi, Y. Mizukami, S. Kasahara, Y. Matsuda, T. Shibauchi, H. Kontani, Y. Uwatoko and N. Fujiwara
  • Journal Title: Scientific Reports Volume: 11 Issue: 1 Pages: 17265-17265
  • DOI: 10.1038/s41598-021-96277-9
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Discovery of mesoscopic nematicity wave in iron-based superconductors (2021)
  • Author(s): Shimojima T.、Motoyui Y.、Taniuchi T.、Bareille C.、Onari S.、Kontani H.、Nakajima M.、Kasahara S.、Shibauchi T.、Matsuda Y.、Shin S.
  • Journal Title: Science Volume: 373 Issue: 6559 Pages: 1122-1125
  • DOI: 10.1126/science.abd6701
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Quasiparticle Nodal Plane in the Fulde-Ferrell-Larkin-Ovchinnikov State of FeSe (2021)
  • Author(s): Kasahara S.、Suzuki H.、Machida T.、Sato Y.、Ukai Y.、Murayama H.、Suetsugu S.、Kasahara Y.、Shibauchi T.、Hanaguri T.、Matsuda Y.
  • Journal Title: Physical Review Letters Volume: 127 Issue: 25 Pages: 257001-257001
  • DOI: 10.1103/physrevlett.127.257001
  • Peer Reviewed
• [Presentation] Fulde-Ferrell-Larkin-Ovchinnikov States in the BCS-BEC-Crossover Superconductor FeSe (2022)
  • Author(s): S. Kasahara
  • Organizer: The 13th International Conference on Materials and Mechanisms of Superconductivity & High Temperature Superconductors
  • Int'l Joint Research / Invited
• [Presentation] Fulde-Ferrell-Larkin-Ovchinnikov States in the BCS-BEC-Crossover Superconductor FeSe (2021)
  • Author(s): Shigeru Kasahara
  • Organizer: 18th International Vortex Conference 2021 (Vortex 2021)
  • Int'l Joint Research / Invited
• [Presentation] FeSeにおけるFFLO超伝導相 (2021)
  • Author(s): 笠原 成
  • Organizer: 日本物理学会 2021年秋季大会
  • Invited