Designing emergent phases based on dimer structure in solids

2022 Fiscal Year Final Research Report

• Project/Area Number: 17K05533
• 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: The University of Tokyo
• Principal Investigator: Hotta Chisa 東京大学, 大学院総合文化研究科, 教授 (50372909)
• Project Period (FY): 2017-04-01 – 2023-03-31
• Keywords: 強相関 / 量子磁性 / 量子ダイナミクス / ネマティック

Outline of Final Research Achievements

The project focuses on the role of dimerized structure in low dimensional correlated systems. Three kinds of systems are studied from different aspects; (1) spin-1/2 dimer based triangular lattice and spin-1 dimer based triangular lattice quantum magnets are studied numerically. both showing quantum nematic orders. The enhancement of quantum fluctuation is a key to have such states and for spin-1/2 the inter-dimer ring exchange interaction plays a crucial role, while for spin-1 system, the incresed dimer degrees of freedom turned out to be important.(2) Quantum critical dynamics of transverse Ising model on a triangular lattice is obtained by the quantum Monte Carlo method using our newly developed framework. This gives the low energy description of the dielectrics of the organic dimer-Mott insulating state. (3) Two-step spin crossover transition in the classical high/low spin states is found to occur due to enthalpic effect,

Free Research Field

物性理論

Academic Significance and Societal Importance of the Research Achievements

Ba3MRu2O9や kappa-ET2Xでみられるスピン液体や誘電異常といった、学術的にも注目されている実験結果に対して、理論的な解釈を与えることができた。またこれまでほとんど有意なアプローチが知られていなかった、バルク系（サイズが大きな系）の量子多体ダイナミクスの計算手法をこれらの研究を通して新たに開発することができた。