Studies on novel ground states and the mechanism of pressure-induced superconductivities in organic triangular-lattice Mott insulators

• Project/Area Number: 21740255
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Single-year Grants
• Research Field: Condensed matter physics II
• Research Institution: Kyoto University
• Principal Investigator: ITOU Tetsuaki Kyoto University, 大学院・人間・環境学研究科, 助教 (50402748)
• Project Period (FY): 2009 – 2010
• Project Status: Completed (Fiscal Year 2010)
• Budget Amount: ¥4,420,000 (Direct Cost: ¥3,400,000、Indirect Cost: ¥1,020,000); Fiscal Year 2010: ¥1,950,000 (Direct Cost: ¥1,500,000、Indirect Cost: ¥450,000); Fiscal Year 2009: ¥2,470,000 (Direct Cost: ¥1,900,000、Indirect Cost: ¥570,000)
• Keywords: 有機導体 / スピン液体 / スピンギャップ / 超伝導

Research Abstract

Theorists have considered that exotic magnetism and superconductivity are possibly realized in triangular-lattice systems. I have experimentally revealed that organic triangular-lattice X[Pd(dmit)_2]_2 systems shows these exotic states. The system X=(C_2H_5)(CH_3)_3Sb was found to show a quantum spin-liquid state. I also found that the ground state of this quantum spin liquid has exotic hidden order unforeseen by classical physics. I revealed that the system X=(C_2H_5)(CH_3)_3P shows exotic superconductivity which is different from the usual d_<x2-y2> superconductivity mediated by (π, π) antiferromagnetic fluctuations.

Research Products

• [Journal Article] Instability of a quantum spin liquidin an organic triangular-latticeantiferromagnet (2010)
  • Author(s): T. Itou, A. Oyamada, S. Maegawa, R.Kato
  • Journal Title: Nature Physics 6 Pages: 673-676
  • Peer Reviewed
• [Journal Article] Instability of a quantum spin liquid in an organic triangular-lattice antiferromagnet (2010)
  • Author(s): T.Itou
  • Journal Title: Nature Physics Volume: 6 Pages: 673-676
  • Peer Reviewed
• [Journal Article] Superconductivity on the border of aspin-gapped Mott insulator: NMR studies ofthe quasi-two-dimensional organic systemEtMe_3P[Pd(dmit)_2]_2 (2009)
  • Author(s): T. Itou, A. Oyamada, S. Maegawa, K. Kubo,H. M. Yamamoto, R. Kato
  • Journal Title: Physical Review B 79 174517(Editors' suggestionに選定) Pages: 1-6
  • Peer Reviewed
• [Journal Article] 13C NMR study of the spin-liquid state inthe triangular quantum antiferromagnetEtMe__3Sb[Pd(dmit)_2]_2 (2009)
  • Author(s): T. Itou, A. Oyamada, S. Maegawa, M.Tamura, R. Kato
  • Journal Title: Journal of Physics: Conference Series 145 012039 Pages: 1-4
  • Peer Reviewed
• [Journal Article] 有機三角格子スピン系EtMe3Sb[Pd(dmit)2]2における量子スピン液体 (2009)
  • Author(s): 伊藤哲明
  • Journal Title: 京都大学低温センター誌 15 Pages: 3-11
  • NAID: 120003850809
  • Peer Reviewed
• [Journal Article] Superconductivity on the border of a spin-gapped Mott insulator : NMR studies of the quasi-two-dimensional organic system EtMe_3P[Pd(dmit)_2]_2 (2009)
  • Author(s): T.Itou
  • Journal Title: Physical Review B 79
  • Peer Reviewed
• [Journal Article] 有機三角格子スピン系EtMe_3Sb[Pd(dmit)_2]_2における量子スピン液体 (2009)
  • Author(s): 伊藤哲明
  • Journal Title: 京都大学低温物質科学研究センター誌 15 Pages: 3-11
  • Peer Reviewed
• [Journal Article] Ground state of the organic spin-liquid material EtMe_3Sb[Pd(dmit)_2]_2
  • Author(s): T.Itou
  • Journal Title: Journal of Physics : Conference Series Volume: (印刷中)
  • Peer Reviewed
• [Journal Article] NMR study of quantum spin liquid and its phase transition in the organic spin-1/2 triangular lattice antiferromagnet EtMe_3Sb[Pd(dmit)_2]_2
  • Author(s): S.Maegawa
  • Journal Title: Journal of Physics : Conference Series Volume: (印刷中)
  • Peer Reviewed
• [Presentation] NMR によるフラストレート三角格子X[Pd(dmit)_2]_2 系における新奇磁性 (2011)
  • Author(s): 伊藤哲明
  • Organizer: 超伝導の研究日本物理学会 第66 回年次大会 若手奨励賞記念講演
  • Place of Presentation: 新潟大学(東北大震災の為、延期)
  • Year and Date: 2011-03-28
• [Presentation] NMRによるフラストレート三角格子X[Pd(dmit)_2]_2系における新奇磁性・超伝導の研究 (2011)
  • Author(s): 伊藤哲明
  • Organizer: 日本物理学会第66回年次大会
  • Place of Presentation: 新潟大学(招待講演)(東北大震災の為、延期)
  • Year and Date: 2011-03-28
• [Presentation] 三角格子Mott 絶縁体スピン液体物質EtMe3Sb[Pd(dmit)_2]_2 の単一単結晶13C-NMR (2011)
  • Author(s): 久保田健朗
  • Organizer: 日本物理学会 第66 回年次大会
  • Place of Presentation: 新潟大学(東北大震災の為中止。発表は成立扱い)
  • Year and Date: 2011-03-27
• [Presentation] 三角格子Mott絶縁体スピン液体物質EtMe_3Sb[Pd(dmit)_2]_2の単一単結晶^<13>C-NMR (2011)
  • Author(s): 久保田健朗
  • Organizer: 日本物理学会第66回年次大会
  • Place of Presentation: 新潟大学(東北大震災の為、中止。発表は成立扱い)
  • Year and Date: 2011-03-27
• [Presentation] Ground state of the organic spin liquid material EtMe3Sb[Pd(dmit)_2]_2 (2011)
  • Author(s): T.Itou
  • Organizer: International Conference on Frustration in Condensed Matter (ICFCM)
  • Place of Presentation: Sendai International Center (Sendai, Japan)
  • Year and Date: 2011-01-11
• [Presentation] NMR study of quantum spin liquid and its phase transition in the organic spin-1/2 triangular lattice antiferromagnet EtMe3Sb[Pd(dmit)2]2 (2011)
  • Author(s): S.Maegawa
  • Organizer: International Conference on Frustration in Condensed Matter (ICFCM)
  • Place of Presentation: Sendai International Center (Sendai, Japan)
  • Year and Date: 2011-01-11
• [Presentation] Ground state of the organic spin liquid material EtMe_3Sb[Pd(dmit)_2]_2 (2011)
  • Author(s): T.Itou
  • Organizer: International Conference on Frustration in Condensed Matter
  • Place of Presentation: 仙台国際センター
  • Year and Date: 2011-01-11
• [Presentation] NMR study of quantum spin liquid and its phase transition in the organic spin-1/2 triangular lattice antiferromagnet EtMe_3Sb[Pd(dmit)_2]_2 (2011)
  • Author(s): S.Maegawa
  • Organizer: International Conference on Frustration in Condensed Matter
  • Place of Presentation: 仙台国際センター
  • Year and Date: 2011-01-11
• [Presentation] 13C-NMR でみたEtMe3Sb[Pd(dmit)_2]_2 における三角格子量子スピン液体状態 (2010)
  • Author(s): 久保田健朗
  • Organizer: 日本物理学会 2010 年 秋季大会
  • Place of Presentation: 大阪府立大学
  • Year and Date: 2010-09-25
• [Presentation] ^<13>C-NMRでみたEtMe_3Sb[Pd(dmit)_2]_2における三角格子量子スピン液体状態 (2010)
  • Author(s): 久保田健朗
  • Organizer: 日本物理学会2010年秋季大会
  • Place of Presentation: 大阪府立大学
  • Year and Date: 2010-09-25
• [Presentation] Spin liquid state and its instability in the organic triangular 1/2-spin system EtMe3Sb[Pd(dmit)_2]_2 (2010)
  • Author(s): T.Itou
  • Organizer: Highly Frustrated Magnetism
  • Place of Presentation: Johns Hopkins University (Baltimore, America)
  • Year and Date: 2010-08-03
• [Presentation] Spin liquid state and its instability in the organic triangular 1/2-spin system EtMe_3Sb[Pd(dmit)_2]_2 (2010)
  • Author(s): T.Itou
  • Organizer: Highly Frustrated Magnetism 2010
  • Place of Presentation: Johns Hopkins University(Baltimore, America)
  • Year and Date: 2010-08-03
• [Presentation] Superconductivity on the Border of a Spin-Gapped Mott Insulator : NMR and ac Susceptibility Studies of EtMe3P[Pd(dmit)_2]_2 (2010)
  • Author(s): T.Itou
  • Organizer: ICSM2010 (International Conference on Science and Technology of Synthetic Metals 2010)
  • Place of Presentation: Kyoto International Conference Center (Kyoto, Japan)
  • Year and Date: 2010-07-08
• [Presentation] Spin Liquid, Spin Gap, and Superconductivity in the Triangular-Lattice Mott Insulators X[Pd(dmit)_2]_2 (2010)
  • Author(s): T.Itou
  • Organizer: International Conference on Science and Technology of Synthetic Metals 2010
  • Place of Presentation: 京都国際会議場
  • Year and Date: 2010-07-08
• [Presentation] Exotic Symmetry Breaking in the Quantum Spin Liquid in the Triangular-Lattice Mott Insulator EtMe3Sb[Pd(dmit)_2]_2 (2010)
  • Author(s): T.Kubota
  • Organizer: ICSM2010 (International Conference on Science and Technology of Synthetic Metals 2010)
  • Place of Presentation: Kyoto International Conference Center (Kyoto, Japan)
  • Year and Date: 2010-07-06
• [Presentation] Exotic Symmetry Breaking in the Quantum Spin Liquid in the Triangular-Lattice Mott Insulator EtMe_3Sb[Pd(dmit)_2]_2 (2010)
  • Author(s): T.Kubota
  • Organizer: International Conference on Science and Technology of Synthetic Metals 2010
  • Place of Presentation: 京都国際会議場
  • Year and Date: 2010-07-06
• [Presentation] 13C-NMR studies of the spin liquid material EtMe3Sb[Pd(dmit)_2]_2 (2010)
  • Author(s): 伊藤哲明
  • Organizer: 量子スピン液体ミニ研究会
  • Place of Presentation: 理化学研究所
  • Year and Date: 2010-05-28
• [Presentation] ^<13>C-NMR studies of the spin liquid material EtMe_3Sb[Pd(dmit)_2]_2 (2010)
  • Author(s): 伊藤哲明
  • Organizer: 量子スピン液体ミニ研究会
  • Place of Presentation: 理化学研究所
  • Year and Date: 2010-05-28
• [Presentation] 三角格子スピン液体物質EtMe3Sb[Pd(dmit)_2]_2 (2010)
  • Author(s): 久保田健朗
  • Organizer: の低磁場13C-NMR日本物理学会 第65 回年次大会
  • Place of Presentation: 岡山大学
  • Year and Date: 2010-03-22
• [Presentation] 三角格子スピン液体物質EtMe_3Sb[Pd(dmit)_2]_2の低磁場^<13>C-NMR (2010)
  • Author(s): 久保田健朗
  • Organizer: 日本物理学会 第65回年次大会
  • Place of Presentation: 岡山大学
  • Year and Date: 2010-03-22
• [Presentation] 三角格子有機Mott 絶縁体X[Pd(dmit)_2]_2 (2009)
  • Author(s): 伊藤哲明
  • Organizer: を舞台としたスピン液体、スピンギャップ、圧力下超伝導物性科学領域横断研究会
  • Place of Presentation: 東京大学
  • Year and Date: 2009-11-29
• [Presentation] 三角格子有機Mott絶縁体X[Pd(dmit)_2]_2を舞台としたスピン液体、スピンギャップ、圧力下超伝導 (2009)
  • Author(s): 伊藤哲明
  • Organizer: 物性科学領域横断研究会
  • Place of Presentation: 東京大学
  • Year and Date: 2009-11-29
• [Presentation] 三角格子Mott 絶縁体Pd(dmit)_2塩の分子内側サイト13C-NMR II (2009)
  • Author(s): 伊藤哲明
  • Organizer: 日本物理学会 2009 年秋季大会
  • Place of Presentation: 熊本大学
  • Year and Date: 2009-09-28
• [Presentation] 三角格子Mott絶縁体Pd(dmit)_2塩の分子内側サイト^<13>C-NMR II (2009)
  • Author(s): 伊藤哲明
  • Organizer: 日本物理学会 2009年秋季大会
  • Place of Presentation: 熊本大学
  • Year and Date: 2009-09-28
• [Presentation] The 8th International Symposium on Crystalline Organic Metals (2009)
  • Author(s): T.Itou
  • Organizer: Superconductors and Ferromagnets
  • Place of Presentation: Hilton Niseko Village (Hokkaido, Japan)
  • Year and Date: 2009-09-16
• [Presentation] Spin Liquid, Spin Gap, and Superconductivity in the Triangular-Lattice Mott Insulators X[Pd(dmit)_2]_2 (2009)
  • Author(s): T.Itou
  • Organizer: The 8th International Symposium on Crystalline Organic Metals, Superconductors and Ferromagnets
  • Place of Presentation: Hilton Niseko Village, Hokkaido
  • Year and Date: 2009-09-16
• [Presentation] 有機三角格子Mott 絶縁体X[Pd(dmit)_2]_2 におけるスピン液体・スピンギャップ・圧力下超伝導 (2009)
  • Author(s): 伊藤哲明
  • Organizer: 京都大学基礎物理学研究所セミナー
  • Place of Presentation: 京都大学基礎物理学研究所
  • Year and Date: 2009-06-03
• [Presentation] 有機三角格子Mott絶縁体X[Pd(dmit)_2]_2におけるスピン液体・スピンギャップ・圧力下超伝導 (2009)
  • Author(s): 伊藤哲明
  • Organizer: 京都大学基礎物理学研究所セミナー
  • Place of Presentation: 京都大学基礎物理学研究所
  • Year and Date: 2009-06-03
• [Book] Taylor & Francis (Molecular Quasi-Triangular LatticeAntiferromagnets) in Understanding Quantum PhaseTransitions (2011)
  • Author(s): Reizo Kato, Tetsuaki Itou
  • Publisher: CRC Press
• [Book] Molecular Quasi-Triangular Lattice Antiferromagnets in Understanding Quantum Phase Transitions (2011)
  • Author(s): Reizo Kato, Tetsuaki Itou
  • Total Pages: 25
  • Publisher: CRC Press/Taylor & Francis
• [Remarks] ホームページ等
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• [Remarks]
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