Experimental study on interband effect of magnetic field in strongly correlated Dirac electron system

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K03869
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 13030:Magnetism, superconductivity and strongly correlated systems-related
• Research Institution: National Institute for Materials Science
• Principal Investigator: Konoike Takako 国立研究開発法人物質・材料研究機構, 国際ナノアーキテクトニクス研究拠点, 主任研究員 (70447316)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: 有機伝導体 / ディラック電子

Outline of Final Research Achievements

In this work, we focus on the organic conductor alpha-(BEDT-TTF)2I3, which has linear dispersion under pressure, to detect giant orbital diamagnetism and interband Hall effect due to the interband effect of magnetic field peculiar to Dirac fermions, and to clarify the relation between them. Although we observed diamagnetism, there were concerns about structural changes in some of the samples, and we were unable to determine the origin. On the other hand, we measured the magnetic torque of a recently discovered analog of the Dirac electron system under ambient pressure, alpha-(BETS)2I3, and observed a peculiar temperature dependence. This may reflect the diamagnetic contribution of the Dirac electrons at low temperatures. We have also obtained the first evidence of magnetic order formation below 3.5 K in this compound.

Free Research Field

物性物理学

Academic Significance and Societal Importance of the Research Achievements

本研究では強相関有機ディラック電子系alpha-(BETS)2I3において特異な磁気トルクの振舞いが観測され，磁気秩序の形成を示す初めてのデータを得ることが出来た．強相関のディラック電子は低温で反強磁性秩序を示すことが理論的に示唆されており，本研究で磁気秩序が観測された事は学術的に意義深い．また相対論的ディラック電子の特異な振舞いは従来のデバイス中の電子とは著しく異なり，エレクトロニクス分野への応用においてその基礎物性の解明は社会的にも大きな意義を持つ．