Multidirectionaly thermodynamic study on charge order and charge fluctuation on molecular dimer Mott insulators

• Project/Area Number: 16K05447
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Condensed matter physics II
• Research Institution: Osaka University
• Principal Investigator: Yamashita Satoshi 大阪大学, 理学研究科, 助教 (40587466)
• Project Period (FY): 2016-10-21 – 2020-03-31
• Project Status: Completed (Fiscal Year 2019)
• Budget Amount: ¥4,160,000 (Direct Cost: ¥3,200,000、Indirect Cost: ¥960,000); Fiscal Year 2018: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000); Fiscal Year 2017: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000); Fiscal Year 2016: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
• Keywords: 電荷秩序 / 分子性導体 / 強相関 / 熱容量測定 / 量子スピン液体 / 誘電測定 / スピン液体 / 強相関電子系 / 分子性固体 / 物性実験

Outline of Final Research Achievements

We have performed heat capacity measurements and thermoelectric power measurements for two solid solution systems in order to clarify the charge order transition behavior and the excitation structure in molecular dimer Mott insulating system, which have phase boundary between quantum spin liquid phase and charge ordered phase. The both results of the heat capacity measurements and the thermoelectric power measurements indicate a higher order transition character in charge ordering of present systems. It is also suggested the non-magnetic transition and forming of charge ordering can be occurred independently. We found a new low-energy excitation structure distinguished from gap-less excitation in spin liquid state. A possibility of short range charge ordering was also suggested.

Academic Significance and Societal Importance of the Research Achievements

分子ダイマー型Mott絶縁体系の電荷秩序転移が高次相転移的な性質を持ち、温度低下に従って徐々に電荷秩序が成長するという特徴は、本系においては短距離の電荷秩序形成が可能であることを示している。量子スピン液体領域の電荷秩序相境界近傍において、ギャップレス励起とは別種の低エネルギー励起を観測したこととを合わせて考察すると、量子スピン液体領域においても小規模の電荷秩序形成やその駆動力となる電荷揺らぎの影響が存在することを示唆している。この結果は、電荷揺らぎに焦点をあてることで量子スピン液体相の実現機構を解明できる可能性を示している。

Research Products

• [Int'l Joint Research] ケンブリッジ大学(英国)
• [Journal Article] Phonon Glass Induced by Electron Correlation (2019)
  • Author(s): T. Nomoto, S. Yamashita, H. Akutsu, Y. Nakazawa, and A. I. Krivchikov
  • Journal Title: J. Phys. Chem. Soc. Jpn. Volume: 88 Issue: 7 Pages: 0736011-4
  • DOI: 10.7566/jpsj.88.073601
  • NAID: 40021949244
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Construction of a thermal conductivity measurement system for small single crystals of organic conductors (2019)
  • Author(s): Tetsuya Nomoto, Shusaku Imajo, Satoshi Yamashita,Hiroki Akutsu, Yasuhiro Nakazawa, Alexander I. Krivchikov
  • Journal Title: Journal of Thermal Analysis and Calorimetry Volume: 135 Issue: 5 Pages: 2831-2836
  • DOI: 10.1007/s10973-018-7799-1
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Mobility of hydrated alkali metal ions in metallosupramolecular ionic crystals (2018)
  • Author(s): Nobuto Yoshinari, Satoshi Yamashita, Yosuke Fukuda, Yasuhiro Nakazawa, Takumi Konno
  • Journal Title: Chemical Science Volume: 10 Issue: 2 Pages: 587-593
  • DOI: 10.1039/c8sc04204g
  • Peer Reviewed
• [Journal Article] Thermodynamic Investigation by Heat Capacity Measurements of k-type Dimer-Mott Organic Compounds with Chemical Pressure Tuning (2018)
  • Author(s): Yuki Matsumura, Shusaku Imajo, Satoshi Yamashita, Hiroki Akutsu and Yasuhiro Nakazawa
  • Journal Title: International Journal of Modern Physics B Volume: 32 Issue: 17 Pages: 18400241-7
  • DOI: 10.1142/s0217979218400246
  • Peer Reviewed / Open Access
• [Journal Article] Fermi surface in the absence of a Fermi liquid in the Kondo insulator SmB6 (2018)
  • Author(s): M. Hartstein, W. H. Toews S. Yamashita(8th author), Suchitra E. Sebastian et al
  • Journal Title: Nature Physics Volume: 14 Issue: 2 Pages: 166-172
  • DOI: 10.1038/nphys4295
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Thermodynamics of the quantum spin liquid state of the single-component dimer Mott system k-H3(Cat－EDT－TTF)2. (2017)
  • Author(s): Satoshi Yamashita, Yasuhiro Nakazawa, Akira Ueda, Hatsumi Mori
  • Journal Title: Physical Review B Volume: 95 Issue: 18
  • DOI: 10.1103/physrevb.95.184425
  • Peer Reviewed
• [Journal Article] Increase in the Magnetic Ordering Temperature (Tc) as a Function of the Applied Pressure for A2Mn[Mn(CN)6] (A = K, Rb, Cs) Prussian Blue Analogues (2017)
  • Author(s): Masataka Sugimoto, Satoshi Yamashita, Hiroki Akutsu, Yasuhiro Nakazawa, J. G. DaSilva, C.M. Kareis, Joel S. Miller
  • Journal Title: Inorganic Chemistry Volume: 56 Issue: 17 Pages: 10452-10457
  • DOI: 10.1021/acs.inorgchem.7b01402
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Unusual Magnetic State with Dual Magnetic Excitations in the Single Crystal of S = 1/2 Kagome Lattice Antiferromagnet CaCu3(OH)6Cl2・0.6H2O (2017)
  • Author(s): H. Yoshida, N. Noguchi, Y. Matsushita, Y. Ishii, Y. Ihara, M. Oda, H. Okabe, S. Yamashita, Y. Nakazawa, A. Takata, T. Kida, Y. Narumi, and M. Hagiwara
  • Journal Title: Journal of the Physical Society of Japan Volume: 86 Issue: 3 Pages: 033704-033704
  • DOI: 10.7566/jpsj.86.033704
  • NAID: 210000134285
  • Peer Reviewed / Open Access / Acknowledgement Compliant
• [Presentation] 分子性導体における電荷ガラス状態の電場制御 (2019)
  • Author(s): 山下智史，野本哲也，圷 広樹，中澤康浩
  • Organizer: 第 55 回熱測定討論会
• [Presentation] Thermodynamic Investigation on the Excitation Structure of the Organic Quantum Spin Liquid System (2019)
  • Author(s): Satoshi Yamashita
  • Organizer: The Seventh International Symposium on the New Frontiers of Thermal Studies of Material
  • Int'l Joint Research / Invited
• [Presentation] θ-(BEDT-TTF)2RbZn(SCN)4における電荷ガラス状態の低温熱容量 (2019)
  • Author(s): 山下智史，野本哲也，圷広樹，中澤康浩
  • Organizer: 日本物理学会第74回年次大会
• [Presentation] Systematic Heat Capacity Measurements for Quantum Spin Liquid Phase in Dimer Mott system (2018)
  • Author(s): Satoshi Yamashita
  • Organizer: The 6th Joint Meeting of the 73rd Calorimetry Conference and the 25th International Conference on Chemical Thermodynamics (CALCON-ICCT 2018)
  • Int'l Joint Research / Invited
• [Presentation] Thermodynamic Study on Charge-Ordering in Organic Dimer Mott Systems (2018)
  • Author(s): Satoshi Yamashita
  • Organizer: International Symposium of Structural Thermodynamics for Young Thermodynamisists
  • Int'l Joint Research
• [Presentation] 電場下における物性測定手法 (2018)
  • Author(s): 山下智史
  • Organizer: 日本化学会第98春季年会
  • Invited
• [Presentation] 電荷秩序相近傍のX[M(dmit)2]2(M=Pd,Pt)の低温熱容量 (2017)
  • Author(s): 山下智史，中澤康浩，上田康平，加藤礼三
  • Organizer: 日本物理学会第72回年次大会
  • Place of Presentation: 大阪（大阪大学豊中キャンパス）
  • Year and Date: 2017-03-17
• [Presentation] Dimer-Mott絶縁体における電荷秩序形成機構に関する熱的研究 (2017)
  • Author(s): 山下智史，中澤康浩，上田康平，加藤礼三
  • Organizer: 第53回熱測定討論会
• [Presentation] EtMe3Sb[Pd1-xPtx(dmit)2]2混晶塩の電荷秩序状態に関する熱的研究 (2017)
  • Author(s): 山下智史，中澤康浩，上田康平，加藤礼三
  • Organizer: 日本物理学会2017年秋季大会
• [Presentation] 分子性電荷移動塩の高圧下比熱 (2017)
  • Author(s): 山下智史
  • Organizer: 東北大金研ワークショップ「多自由度が協奏する分子システムの科学」
• [Remarks] 阪大化学熱学レポート No.40
  • URL: http://www.chem.sci.osaka-u.ac.jp/lab/micro/report/rctes/2019/index.html.ja
• [Remarks] 阪大化学熱学レポート，X[Pd(dmit)2]2系の低温熱容量と電子構造の関係性
  • URL: http://www.chem.sci.osaka-u.ac.jp/lab/micro/report/rcst/2018/index.html.ja
• [Remarks] 阪大化学熱学レポート，量子スピン液体物質の低温熱容量における乱れの効果
  • URL: http://www.chem.sci.osaka-u.ac.jp/lab/micro/report/rcst/2018/index.html.ja
• [Remarks] 阪大化学熱学レポート 水素結合型量子スピン液体物質κ-H3(Cat-EDT-TTF)2の低温熱容量
  • URL: http://www.chem.sci.osaka-u.ac.jp/lab/micro/report/rcst/2017/index.html.ja