Exotic electroinc state and quantum condensate in ultra-shallow band materials(Fostering Joint International Research)

• Project/Area Number: 15KK0160
• Research Category: Fund for the Promotion of Joint International Research (Fostering Joint International Research)
• Allocation Type: Multi-year Fund
• Research Field: Condensed matter physics II
• Research Institution: Kyoto University
• Principal Investigator: Shigeru Kasahara 京都大学, 理学研究科, 特定准教授 (10425556)
• Project Period (FY): 2016 – 2019
• Project Status: Completed (Fiscal Year 2019)
• Budget Amount: ¥14,300,000 (Direct Cost: ¥11,000,000、Indirect Cost: ¥3,300,000)
• Keywords: 超シャロウバンド / 鉄系超伝導 / BCS-BECクロスオーバー / ネマティック量子臨界点 / 新奇超伝導相 / 軌道選択 / FFLO状態 / 熱輸送測定 / 強磁場測定 / 低温高磁場相 / 熱伝導率 / 超伝導ギャップ構造 / ネマティシティ / 準粒子励起 / 強相関電子系 / 非従来型超伝導 / ネマティック転移

Outline of Final Research Achievements

The superconducting semimetal FeSe has been found to be deep inside the BCS-BEC crossover regime. In this work, a team of scientists has investigated heat transports in FeSe in intensive fields up to 35 T and found compelling evidence of a distinct high-field superconducting phase which is separated from the usual superconducting phase via a first-order phase transition. This high-field phase is attributed to an exotic state, the so-called FFLO phase, first predicted in 1964. In the isovalently substituted FeSe1-xSx superconductors, the team found non-Fermi liquid charge transports in the vicinity of a novel type of quantum critical point (QCP) of pure nematic order without accompanying other orders. The set of anomalous charge transport properties show striking resemblance to those reported in high-Tc cuprates and heavy Fermion superconductors. A common set of anomalous charge transport properties captures a universal feature of the non-Fermi liquid transport properties near the QCP.

Academic Significance and Societal Importance of the Research Achievements

これまでヘリウム3温度域において18Tを超える極限環境での熱伝導率の精密測定を行える環境は世界にもなかった。本研究では、世界屈指の強磁場施設の一つであるナイメーヘン強磁場研究所においてヘリウム3温度域、最大35テスラまでの強磁場熱伝導率測定を確立し、新奇な超伝導状態の探索と解明を可能とした。これは本研究で対象とした研究に留まらず、様々な系において未踏の実験を可能とした意義深いものといえる。

Research Products

• [Int'l Joint Research] 欧州強磁場研究機構・ナイメーヘン強磁場研究所(オランダ) (2019)
• [Int'l Joint Research] 欧州強磁場研究機構・ドレスデン強磁場研究所(ドイツ) (2017)
• [Journal Article] Evidence for an FFLO State with Segmented Vortices in the BCS-BEC-Crossover Superconductor FeSe (2020)
  • Author(s): S. Kasahara, Y. Sato, S. Licciardello, M. Culo, S. Arsenijevic, T. Ottenbros, T. Tominaga, J. Boker, I. Eremin, T. Shibauchi, J. Wosnitza, N. E. Hussey, and Y. Matsuda,
  • Journal Title: Phys. Rev. Lett. Volume: 124 Issue: 10 Pages: 107001-107001
  • DOI: 10.1103/physrevlett.124.107001
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Coexistence of orbital and quantum critical magnetoresistance in FeSe1-xSx (2019)
  • Author(s): Licciardello S.、Maksimovic N.、Ayres J.、Buhot J.、Culo M.、Bryant B.、Kasahara S.、Matsuda Y.、Shibauchi T.、Nagarajan V.、Analytis J. G.、Hussey N. E.
  • Journal Title: Physical Review Research Volume: 1 Issue: 2 Pages: 023011-023011
  • DOI: 10.1103/physrevresearch.1.023011
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Photo-induced possible superconducting state with long-lived disproportionate band filling in FeSe (2019)
  • Author(s): Takeshi Suzuki*, Takashi Someya, Takahiro Hashimoto, Shoya Michimae, Mari Watanabe, Masami Fujisawa, Teruto Kanai, Nobuhisa Ishii, Jiro Itatani, Shigeru Kasahara, Yuji Matsuda, Takasada Shibauchi, Kozo Okazaki*, and Shik Shin*
  • Journal Title: Commun. Phys. Volume: 2 Issue: 1 Pages: 115-115
  • DOI: 10.1038/s42005-019-0219-4
  • Peer Reviewed / Open Access
• [Journal Article] Ultrafast nematic-orbital excitation in FeSe (2019)
  • Author(s): T. Shimojima, Y. Suzuki, A. Nakamura, N. Mitsuishi, S. Kasahara, T. Shibauchi, Y. Matsuda, Y. Ishida, S. Shin, K. Ishizaka
  • Journal Title: Nature Communications Volume: 10 Issue: 1 Pages: 1946-1946
  • DOI: 10.1038/s41467-019-09869-5
  • Peer Reviewed / Open Access
• [Journal Article] Evolution of the low-temperature Fermi surface of superconducting FeSe1-xSx across a nematic phase transition (2019)
  • Author(s): Coldea Amalia I.、Blake Samuel F.、Kasahara Shigeru、Haghighirad Amir A.、Watson Matthew D.、Knafo William、Choi Eun Sang、McCollam Alix、Reiss Pascal、Yamashita Takuya、Bruma Mara、Speller Susannah C.、Matsuda Yuji、Wolf Thomas、Shibauchi Takasada、Schofield Andrew J.
  • Journal Title: npj Quantum Materials Volume: 4 Issue: 1 Pages: 2-2
  • DOI: 10.1038/s41535-018-0141-0
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Electrical resistivity across a nematic quantum critical point (2019)
  • Author(s): Licciardello S.、Buhot J.、Lu J.、Ayres J.、Kasahara S.、Matsuda Y.、Shibauchi T.、Hussey N. E.
  • Journal Title: Nature Volume: 567 Issue: 7747 Pages: 213-217
  • DOI: 10.1038/s41586-019-0923-y
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Quantum Vortex Core and Missing Pseudogap in the Multiband BCS-BEC Crossover Superconductor FeSe (2019)
  • Author(s): Hanaguri T.、Kasahara S.、B?ker J.、Eremin I.、Shibauchi T.、Matsuda Y.
  • Journal Title: Physical Review Letters Volume: 122 Issue: 7 Pages: 77001-77001
  • DOI: 10.1103/physrevlett.122.077001
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] 77Se-NMR Study under Pressure on 12%-S Doped FeSe (2019)
  • Author(s): Kuwayama Takanori、Matsuura Kohei、Mizukami Yuta、Kasahara Shigeru、Matsuda Yuji、Shibauchi Takasada、Uwatoko Yoshiya、Fujiwara Naoki
  • Journal Title: Journal of the Physical Society of Japan Volume: 88 Issue: 3 Pages: 033703-033703
  • DOI: 10.7566/jpsj.88.033703
  • NAID: 210000135114
  • Peer Reviewed
• [Journal Article] Two distinct superconducting pairing states divided by the nematic end point in FeSe1-xSx (2018)
  • Author(s): Hanaguri Tetsuo、Iwaya Katsuya、Kohsaka Yuhki、Machida Tadashi、Watashige Tatsuya、Kasahara Shigeru、Shibauchi Takasada、Matsuda Yuji
  • Journal Title: Science Advances Volume: 4 Issue: 5
  • DOI: 10.1126/sciadv.aar6419
  • NAID: 120006471158
  • Peer Reviewed / Open Access
• [Journal Article] Abrupt change of the superconducting gap structure at the nematic critical point in FeSe1?xSx (2018)
  • Author(s): Sato Yuki、Kasahara Shigeru、Taniguchi Tomoya、Xing Xiangzhuo、Kasahara Yuichi、Tokiwa Yoshifumi、Yamakawa Youichi、Kontani Hiroshi、Shibauchi Takasada、Matsuda Yuji
  • Journal Title: Proceedings of the National Academy of Sciences Volume: 115 Issue: 6 Pages: 1227-1231
  • DOI: 10.1073/pnas.1717331115
  • Peer Reviewed / Int'l Joint Research
• [Presentation] FeSeの強磁場熱輸送測定：FFLO状態 (2020)
  • Author(s): 笠原成, 佐藤雄貴, S. Licciardello, M. Culo, S. Arsenijevic, T. Ottenbros, 冨永貴弘, J.Boker, I. Eremin, 芝内孝禎, J. Wosnitza, N. E. Hussey, 松田祐司
  • Organizer: 第75回日本物理学会年次大会(2020年)（名古屋大）：現地開催中止
• [Presentation] FeSeにおけるFFLO超伝導 (2019)
  • Author(s): 笠原成
  • Organizer: 第27回 渦糸物理 ワークショップ
  • Invited
• [Presentation] FeSe における強磁場超伝導相：FFLO 状態 (2019)
  • Author(s): 笠原成
  • Organizer: 基研研究会 「電子相関が生み出す超伝導現象の未解決問題と新しい潮流」
  • Invited
• [Presentation] Nematic Phase Transition at the Onset of Pseudogap in Cuprates (2018)
  • Author(s): Shigeru Kasahara
  • Organizer: Plasma 2019 Workshop, Jan. 18- 21, 2018. Univ. Central Florida, Orlando, FL, USA
  • Invited
• [Presentation] Nematic transition at the onset of pseudogap in cuprates (2018)
  • Author(s): Shigeru Kasahara
  • Organizer: Energy and Environmental Applications (CMCEE-2018), Jul. 22-27, 2018, Suntec, Singapore
  • Invited
• [Presentation] Nematic transition at the onset of pseudogap in cuprates (2018)
  • Author(s): Shigeru Kasahara
  • Organizer: International Workshop on Recent Progress in Superconductivity, Jul. 13-15, 2018, Peyongchang, Korea
  • Invited
• [Presentation] 銅酸化物高温超伝導体における新奇なネマティシティ (2018)
  • Author(s): 笠原成
  • Organizer: 京都大学基礎物理学研究所研究会「多自由度電子状態と電子相関が生み出す新奇超伝導の物理」, 2018 年5 月 7-9日, 京都大学, 京都市
  • Invited
• [Presentation] Abrupt Change of the Superconducting Gap Structure at the Nematic Quantum Critical Point in FeSe1-xSx (2018)
  • Author(s): Y. Sato, S. Kasahara, T. Taniguchi, X.Z. Xing, Y. Kasahara, Y. Tokiwa, Y. Yamakawa, H. Kontani, T. Shibauchi, Y. Matsuda
  • Organizer: American Physical Society, March Meeting
  • Int'l Joint Research
• [Presentation] Two Distinct Superconducting Pairing States Divided by the Nematic End Point in FeSe1-xSx (2018)
  • Author(s): T. Hanaguri, K. Iwaya, Y. Kohsaka, T. Machida, T. Watashige, S. Kasahara, T. Shibauchi, Y. Matsuda
  • Organizer: American Physical Society, March Meeting
  • Int'l Joint Research
• [Presentation] Quasiparticle excitations of FeSe in the vicinity of the BCS-BEC crossover (2017)
  • Author(s): S. Kasahara
  • Organizer: The 16th International Workshop on Vortex Matter in Superconductors (VORTEX2017), Natal, Brazil.
  • Int'l Joint Research / Invited
• [Presentation] FeSe1-xSxにおける異方的超伝導ギャップ構造 (2017)
  • Author(s): 笠原成
  • Organizer: 京都大学・基研研究会 「超伝導研究の最先端： 多自由度、非平衡、電子相関、トポロジー、人工制御」
  • Invited
• [Presentation] 鉄系超伝導体Fe(Se,S)の超伝導ギャップ異方性 (2017)
  • Author(s): 谷口智哉, 佐藤雄貴, Xiangzhuo Xing, 笠原成, 常盤欣文, 笠原裕一, 芝内孝禎, 松田祐司
  • Organizer: 日本物理学会 2017年秋季大会
• [Presentation] Fe(Se,S)のバンド構造と超伝導に対するネマティシティの効果 (2017)
  • Author(s): 花栗哲郎, 岩谷克也, 幸坂祐生, 町田理, 綿重達哉, 笠原成, 芝内孝禎, 松田祐司
  • Organizer: 日本物理学会 2017年秋季大会
• [Presentation] 鉄系超伝導体FeSe1-xSxの温度・圧力・化学置換の三次元電子相図 (2017)
  • Author(s): 杉村優一, 松浦康平, 新井佑基, 向笠清隆, 水上雄太, 綿重達哉, 笠原成, 松田祐司, 上床美也, 芝内孝禎
  • Organizer: 日本物理学会 2017年秋季大会
• [Presentation] FeSe1-xSx (x=0.12) の核磁気共鳴 (2017)
  • Author(s): 桑山昂典, 藤原直樹, 松浦康平, 水上雄太, 笠原成, 松田祐司, 芝内孝禎, 上床美也
  • Organizer: 日本物理学会 2017年秋季大会
• [Presentation] パルス電流を用いたFeSe単結晶の渦糸フロー測定 (2017)
  • Author(s): 高石浩行, 家永紘一郎, 金子真一, 笠原成, 松田祐司, 大熊哲
  • Organizer: 日本物理学会 2017年秋季大会
• [Presentation] 高次高調波レーザー時間分解光電子分光法によるFeSeのコヒーレントフォノン観測 (2017)
  • Author(s): 鈴木剛, 染谷隆史, 橋本嵩広, 道前翔矢, 渡邉真莉A, 藤澤正美, 金井輝人, 石井順久, 板谷治郎, 芝内孝禎, 笠原成, 松田祐司, 岡崎浩 三, 辛埴
  • Organizer: 日本物理学会 2017年秋季大会
• [Presentation] レーザー励起光電子顕微鏡によるFeSeにおけるネマティック秩序のドメイン観察 (2017)
  • Author(s): 元結啓仁, 谷内敏之, 下志万貴博, 岡崎浩三, 笠原成, 芝内孝禎, 松田裕司, 辛埴
  • Organizer: 日本物理学会 2017年秋季大会
• [Remarks] 京都大学量子凝縮物性研究室
  • URL: http://kotai2.scphys.kyoto-u.ac.jp/index.php?Top
• [Remarks] 京都大学量子凝縮物性研究室
  • URL: http://kotai2.scphys.kyoto-u.ac.jp/