Study of spin chirality in quantum spin liquids by thermal-Hall measurement

2022 Fiscal Year Final Research Report

• Project/Area Number: 19H01848
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 13030:Magnetism, superconductivity and strongly correlated systems-related
• Research Institution: The University of Tokyo
• Principal Investigator: Yamashita Minoru 東京大学, 物性研究所, 准教授 (10464207)
• Project Period (FY): 2019-04-01 – 2023-03-31
• Keywords: 量子スピン液体 / 熱ホール測定 / 熱輸送測定

Outline of Final Research Achievements

In this study, in order to clarify the elementary excitations in the quantum spin liquid phase, we investigated the thermal Hall effect in magnetic insulators to clarify the effect of spin chirality of elementary spin excitations, which has been difficult to measure directly so far.
During the research period, we succeeded in performing thermal Hall measurements in the kagome antiferromagnet Cd-Capellasite, the skyrmion-host ferromagnetic insulator GaV4Se8, the new Kitaev-spin-liquid candidate Na2Co2TeO6, and the antiferro-skyrmion material MnSc2S4. Our successful measurements on these materials provide new knowledge on the relationship between the thermal Hall effect and the spin chirality in magnetic insulators.

Free Research Field

低温物理学

Academic Significance and Societal Importance of the Research Achievements

磁場によって金属中を流れる電流が曲げられるホール効果と同様の現象が、金属の流れない絶縁体中の熱流に対する熱ホール効果として現れることを系統的に研究し、そのメカニズムの一端を明らかにした。特に、磁気スキルミオンのような磁気構造がうみだす創発磁場が電流だけでなく、熱流にも作用することを明らかにした。これらの成果は固体中のスピン構造が生み出す創発磁場の理解と応用を大きく進展させる結果であると考えている。