Exotic quantum phases in conductive multipole systems studied by field-angle-resolved specific heat and entropy

• Project Area: J-Physics: Physics of conductive multipole systems
• Project/Area Number: 18H04306
• Research Category: Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area)
• Allocation Type: Single-year Grants
• Research Institution: The University of Tokyo
• Principal Investigator: 橘高 俊一郎 東京大学, 物性研究所, 助教 (80579805)
• Project Period (FY): 2018-04-01 – 2020-03-31
• Project Status: Completed (Fiscal Year 2019)
• Budget Amount: ¥8,970,000 (Direct Cost: ¥6,900,000、Indirect Cost: ¥2,070,000); Fiscal Year 2019: ¥4,550,000 (Direct Cost: ¥3,500,000、Indirect Cost: ¥1,050,000); Fiscal Year 2018: ¥4,420,000 (Direct Cost: ¥3,400,000、Indirect Cost: ¥1,020,000)
• Keywords: 超伝導ギャップ / 多極子秩序 / 比熱 / エントロピー / 磁場角度依存性 / 隠れた秩序

Outline of Annual Research Achievements

本研究では、【I.多軌道超伝導のギャップ構造】と【II.多極子伝導系における新奇秩序状態】の研究に取り組み、個々の発現機構および普遍的性質に迫ることを目的としている。
本年度、【I】の課題では、昨年発見されたスピン三重項超伝導体の新たな候補物質として注目されるウラン系超伝導体UTe2の磁場角度分解比熱測定を行った。低温比熱の特徴的な磁場角度依存性を見出し、得られた結果をプレプリントサーバーで公表した。さらに、ネマティック超伝導体SrxBi2Se3については超伝導転移温度より高い温度からネマティック電子状態が実現していることを突き止めた。結果をまとめた論文はPhysical Review Letters誌で公表した。昨年度、等方的フルギャップの実験証拠を提供したCd2Re2O7については、ネマティック電子状態の異方性を調べる目的で7 Tの高磁場領域まで磁場角度分解比熱測定を行った。また、Sr2RuO4の超伝導ギャップ構造に関する研究成果を複数の国際ワークショップで発表し、会議参加者と議論を深めた。
【II】の課題では、昨年度に実施したPrTi2Al20の強四極子秩序相に関する研究成果を論文にまとめてJournal of the Physical Society of Japan誌で公表した。URu2Si2の隠れた秩序相については追試を行い、相転移に伴う巨大な比熱の飛びの磁場角度変化を慎重に調べたが、我々の測定精度の範囲では明確なab面内異方性は見られないとの結論に至った。
これまでの一連の研究成果が高く評価され、2019年11月には第14回凝縮系科学賞を受賞した。

Research Progress Status

令和元年度が最終年度であるため、記入しない。

Strategy for Future Research Activity

令和元年度が最終年度であるため、記入しない。

Research Products

• [Int'l Joint Research] Max Planck Institute(ドイツ)
• [Int'l Joint Research] Max Planck Institute(ドイツ)
• [Journal Article] Field-Orientation Effect on Ferro-Quadrupole Order in PrTi2Al20 (2020)
  • Author(s): Kittaka Shunichiro、Taniguchi Takanori、Hattori Kazumasa、Nakamura Shota、Sakakibara Toshiro、Takigawa Masashi、Tsujimoto Masaki、Sakai Akito、Matsumoto Yosuke、Nakatsuji Satoru
  • Journal Title: Journal of the Physical Society of Japan Volume: 89 Issue: 4 Pages: 043701-043701
  • DOI: 10.7566/jpsj.89.043701
  • NAID: 40022211746
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Heavy Fermion State of YbNi2Si3 without Local Inversion Symmetry (2020)
  • Author(s): Nakamura Shota、Hyodo Kazushi、Matsumoto Yuji、Haga Yoshinori、Sato Hitoshi、Ueda Shigenori、Mimura Kojiro、Saiki Katsuyoshi、Iso Kosei、Yamashita Minoru、Kittaka Shunichiro、Sakakibara Toshiro、Ohara Shigeo
  • Journal Title: Journal of the Physical Society of Japan Volume: 89 Issue: 2 Pages: 024705-024705
  • DOI: 10.7566/jpsj.89.024705
  • NAID: 40022155106
  • Peer Reviewed
• [Journal Article] Superconductivity in PtSbS with a Noncentrosymmetric Cubic Crystal Structure (2019)
  • Author(s): Ryosuke Mizutani, Yoshihiko Okamoto, Hayate Nagaso, Youichi Yamakawa, Hiroshi Takatsu, Hiroshi Kageyama, Shunichiro Kittaka, Yohei Kono, Toshiro Sakakibara, and Koshi Takenaka
  • Journal Title: Journal of the Physical Society of Japan Volume: 88 Issue: 9 Pages: 093709-093709
  • DOI: 10.7566/jpsj.88.093709
  • NAID: 40022008736
  • Peer Reviewed
• [Journal Article] Fluctuation-Induced First-Order Transition and Tricritical Point in EuPtSi (2019)
  • Author(s): Sakakibara Toshiro、Nakamura Shota、Kittaka Shunichiro、Kakihana Masashi、Hedo Masato、Nakama Takao、Onuki Yoshichika
  • Journal Title: Journal of the Physical Society of Japan Volume: 88 Issue: 9 Pages: 093701-093701
  • DOI: 10.7566/jpsj.88.093701
  • NAID: 40022008704
  • Peer Reviewed
• [Journal Article] Quasiparticle Evidence for the Nematic State above Tc in SrxBi2Se3 (2019)
  • Author(s): Yue Sun, Shunichiro Kittaka, Toshiro Sakakibara, Kazushige Machida, Jinghui Wang, Jinsheng Wen, Xiangzhuo Xing, Zhixiang Shi, and Tsuyoshi Tamegai
  • Journal Title: Phys. Rev. Lett. Volume: 123 Issue: 2 Pages: 027002-027002
  • DOI: 10.1103/physrevlett.123.027002
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Anisotropic magnetic-field response of quantum critical fluctuations in Ni-doped CeCoIn5 (2019)
  • Author(s): M. Yokoyama, K. Suzuki, K. Tenya, S. Nakamura, Y. Kono, S. Kittaka, and T. Sakakibara
  • Journal Title: Physical Review B Volume: 99 Issue: 5
  • DOI: 10.1103/physrevb.99.054506
  • Peer Reviewed
• [Journal Article] Metamagnetic crossover in the quasikagome Ising Kondo-lattice compound CeIrSn (2018)
  • Author(s): S. Tsuda, C. L. Yang, Y. Shimura, K. Umeo, H. Fukuoka, Y. Yamane, T. Onimaru, T. Takabatake, N. Kikugawa, T. Terashima, H. T. Hirose, S. Uji, S. Kittaka, T. Sakakibara
  • Journal Title: Phys. Rev B. Volume: 98 Issue: 15 Pages: 155147-155147
  • DOI: 10.1103/physrevb.98.155147
  • Peer Reviewed
• [Journal Article] Low-Temperature Magnetization Measurements with Precise Two-Axis Alignment of the Sample Orientation (2018)
  • Author(s): Nakamura Shota、Kasahara Akira、Kittaka Shunichiro、Kono Yohei、Onuki Yoshichika、Sakakibara Toshiro
  • Journal Title: Journal of the Physical Society of Japan Volume: 87 Issue: 11 Pages: 114001-114001
  • DOI: 10.7566/jpsj.87.114001
  • NAID: 210000134999
  • Peer Reviewed
• [Journal Article] Disorder-sensitive nodelike small gap in FeSe (2018)
  • Author(s): Sun Yue、Kittaka Shunichiro、Nakamura Shota、Sakakibara Toshiro、Zhang Peng、Shin Shik、Irie Koki、Nomoto Takuya、Machida Kazushige、Chen Jingting、Tamegai Tsuyoshi
  • Journal Title: Physical Review B Volume: 98 Issue: 6
  • DOI: 10.1103/physrevb.98.064505
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Searching for gap zeros in Sr2RuO4 via field-angle-dependent specific-heat measurement (2018)
  • Author(s): Shunichiro Kittaka, Shota Nakamura, Toshiro Sakakibara, Naoki Kikugawa, Taichi Terashima, Shinya Uji, Dmitry A. Sokolov, Andrew P. Mackenzie, Koki Irie, Yasumasa Tsutsumi, Katsuhiro Suzuki, and Kazushige Machida
  • Journal Title: J. Phys. Soc. Jpn. Volume: 87 Issue: 9 Pages: 0937031-5
  • DOI: 10.7566/jpsj.87.093703
  • NAID: 210000134938
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Field-rotational Magnetocaloric Effect: A New Experimental Technique for Accurate Measurement of the Anisotropic Magnetic Entropy (2018)
  • Author(s): Kittaka Shunichiro、Nakamura Shota、Kadowaki Hiroaki、Takatsu Hiroshi、Sakakibara Toshiro
  • Journal Title: Journal of the Physical Society of Japan Volume: 87 Issue: 7 Pages: 073601-073601
  • DOI: 10.7566/jpsj.87.073601
  • NAID: 210000134879
  • Peer Reviewed / Open Access
• [Presentation] Sr2RuO4における超伝導多重相の検証 (2020)
  • Author(s): 橘高 俊一郎
  • Organizer: J-Physics：多極子伝導系の物理 令和元年度領域全体会議
• [Presentation] 極低温精密比熱測定による超伝導ギャップ構造の決定 (2019)
  • Author(s): 橘高 俊一郎
  • Organizer: 第13回物性科学領域横断研究会 第14回「凝縮系科学賞」受賞講演
  • Invited
• [Presentation] Thermodynamic Evidence for Two Distinct Non-Fermi-Liquid Regimes and a Quantum Critical Line in the Quasi-Kagome Kondo-Lattice CeRhSn (2019)
  • Author(s): S. Kittaka, Y. Kono, S. Tsuda, T. Takabatake, and T. Sakakibara
  • Organizer: International Conference on Strongly Correlated Electron Systems 2019 (SCES2019)
  • Int'l Joint Research
• [Presentation] Thermodynamic study of the superconducting gap structure of Sr2RuO4 (2019)
  • Author(s): S. Kittaka
  • Organizer: J-Physics 2019 International Conference
  • Int'l Joint Research / Invited
• [Presentation] 比熱の磁場角度依存性から見たCd2Re2O7の超伝導ギャップ構造とネマティック状態 (2019)
  • Author(s): 橘高 俊一郎、平井 大悟郎、廣井 善二、町田 一成、榊原 俊郎
  • Organizer: 日本物理学会2019年秋季大会
• [Presentation] Thermodynamic study of the pairing symmetry in Sr2RuO4 (2019)
  • Author(s): S. Kittaka
  • Organizer: Strontium Ruthenate - 25 years of a puzzling superconductor
  • Int'l Joint Research / Invited
• [Presentation] 磁場角度の効果から探るPrTi2Al20とPrIr2Zn20の多極子秩序相 (2019)
  • Author(s): 橘高 俊一郎
  • Organizer: J-Physics地域研究会・本郷
• [Presentation] 擬カゴメ近藤格子CeRhSnにおける量子臨界性の磁場角度依存性 (2019)
  • Author(s): 橘高 俊一郎、河野 洋平、津田 研、高畠 敏郎、榊原 俊郎
  • Organizer: 日本物理学会第74回年次大会
• [Presentation] Field-orientation effect on the hidden-order transition in URu2Si2 (2019)
  • Author(s): S. Kittaka
  • Organizer: Symposium:TPFC 2019
  • Int'l Joint Research
• [Presentation] Sr2RuO4の超伝導ギャップ構造の検証：回転磁場下での比熱測定から (2019)
  • Author(s): 橘高 俊一郎、中村 翔太、榊原 俊郎、菊川 直樹、寺嶋 太一、宇治 進也、Dmitry A. Sokolov、Andrew P. Mackenzie、入江 光輝、堤 康雅、鈴木 雄大、町田 一成
  • Organizer: つくば-柏-本郷 超伝導かけはしプロジェクト ワークショップ（2）
  • Invited
• [Presentation] Multiband full-gap superconductivity in heavy-fermion superconductor CeCu2Si2 revealed by specific-heat measurements (2019)
  • Author(s): S. Kittaka
  • Organizer: Plasma 2019 Workshop
  • Int'l Joint Research / Invited
• [Presentation] Thermodynamic study of Sr2RuO4: identification of the superconducting gap structure (2018)
  • Author(s): S. Kittaka, S. Nakamura, T. Sakakibara, N. Kikugawa, T. Terashima, S. Uji, D. A. Sokolov, A. P. Mackenzie, K. Irie, Y. Tsutsumi, K. Suzuki, and K. Machida
  • Organizer: International Workshop on j-Fermion Physics and Materials
  • Int'l Joint Research / Invited
• [Presentation] 磁場角度分解比熱・エントロピー測定からみたPrTi2Al20の四極子秩序 (2018)
  • Author(s): 橘高 俊一郎、谷口 貴紀、中村 翔太、榊原 俊郎、瀧川 仁、辻本 真規、酒井 明人、松本 洋介、中辻 知
  • Organizer: 日本物理学会2018年秋季大会
• [Presentation] Full-gap superconductivity of Cd2Re2O7 investigated by field-angle-resolved measurement of its specific heat (2018)
  • Author(s): S. Kittaka, D. Hirai, Z. Hiroi, T. Sakakibara
  • Organizer: B01 D01トピカルミーテイング ものづくりシリーズ第３回「物質探索最前線」
• [Presentation] Towards identification of the superconducting gap structure of Sr2RuO4: evidence for a horizontal line node gap from field-angle dependence of its specific heat (2018)
  • Author(s): S. Kittaka, S. Nakamura, T. Sakakibara, N. Kikugawa, T. Terashima, S. Uji, D. A. Sokolov, A. P. Mackenzie, K. Irie, Y. Tsutsumi, K. Suzuki, and K. Machida
  • Organizer: International Conference on Magnetism 2018 (ICM2018)
  • Int'l Joint Research
• [Presentation] Novel quantum phases of conductive multipole systems studied by field-angle-resolved measurements of specific heat and entropy (2018)
  • Author(s): S. Kittaka
  • Organizer: J-Physics平成30年度領域全体会議
• [Remarks] 研究室のホームページ
  • URL: https://www.phys.chuo-u.ac.jp/labs/kittaka/index.html
• [Remarks] 個人のホームページ
  • URL: https://sakaki.issp.u-tokyo.ac.jp/user/kittaka/index.html
• [Remarks] 研究室のホームページ
  • URL: https://sakaki.issp.u-tokyo.ac.jp/