Many body theory with spin-orbit coupling based on fRG

2023 Fiscal Year Final Research Report

• Project/Area Number: 20K22328
• Research Category: Grant-in-Aid for Research Activity Start-up
• Allocation Type: Multi-year Fund
• Review Section: 0202:Condensed matter physics, plasma science, nuclear engineering, earth resources engineering, energy engineering, and related fields
• Research Institution: Kyoto University (2022-2023); Nagoya University (2020-2021)
• Principal Investigator: Tazai Rina 京都大学, 基礎物理学研究所, 助教 (10880023)
• Project Period (FY): 2020-09-11 – 2024-03-31
• Keywords: 超伝導 / 電荷整列秩序 / 多体効果

Outline of Final Research Achievements

Various quantum phase transition were experimentally discovered in the Kagome superconductor AV3Sb5 in 2019. However, the microscopic mechanism of the phase diagram is an open problem.　Here, we analyzed the phase diagram of Kagome superconductors based on the microscopic Hubbard model, taking into account the many-body effect of the electronic system. As a result, we have proposed a mechanism of unidirectional (1Q) charge loop ordering at high temperatures and a first-order phase transition induced by an in-plane magnetic field. We have also studied the transport phenomena induced by the charge-loop current.

Free Research Field

強相関電子系

Academic Significance and Societal Importance of the Research Achievements

これまでに、電場の２次に比例した電圧V(2ω)が面直磁場の向きによって符号を変えるという結果が、実験によって観測されているが、その微視的導出は不十分であった。我々は、電荷ループ秩序の秩序変数を考慮した非相反電気伝導度の解析を行うことで、面直磁場によって符号反転するV(2ω)の解析的な導出をおこなうことができた。