2023 Fiscal Year Final Research Report
Study of band structure and magnetic effects on Dirac semimetals and topological insulators under high pressure
| Project/Area Number |
21K03475
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Review Section |
Basic Section 13030:Magnetism, superconductivity and strongly correlated systems-related
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| Research Institution | University of Hyogo |
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Principal Investigator |
MITO Takeshi 兵庫県立大学, 理学研究科, 教授 (70335420)
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| Project Period (FY) |
2021-04-01 – 2024-03-31
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| Keywords | ディラック半金属 / トポロジカル近藤絶縁体 / 核磁気共鳴 / 高圧 / ベイズ推論 / 第一原理計算 / ワイル半金属 |
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| Outline of Final Research Achievements |
Topological materials have been studied by a nuclear magnetic resonance (NMR) technique, and important results have been obtained that open up this area of research. (1) We obtained experimental evidence of magnetic field effects in black phosphorus, a candidate material for a pressure-induced Dirac semimeal, indicating the existence of the Landau level n=0 (zero mode). (2) In the pressure-induced topological Kondo insulator (TKI) candidate material SmS, we quantitatively discussed electronic correlations and band structure in the semiconducting state and showed that the mechanism of antiferromagnetic ordering in a high-pressure phase above 2 GPa is understood within the itinerant picture. (3) We have made significant progress in the measurements of TKI candidate SmB6 and several Eu Weyl semimetallic candidates. (iv) Pioneering introduction of Bayesian inference and first-principles calculations enabled high reliability and detailed discussion previously unattainable.
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| Free Research Field |
実験固体物理学
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| Academic Significance and Societal Importance of the Research Achievements |
①-④は研究成果欄と対応：①NMR測定によるゼロモード観測が、ディラック電子の存否とその次元性の判断に有効であることを示した。②長年不明であった半導体状態におけるクーロン斥力、バンド幅やギャップ等について初めて微視的かつ定量的な議論を行った。局在描像による磁気秩序が多い希土類化合物において、SmSはそれに適合しないことを示す実験的証拠を得た。③SmB6の表面由来の特性や、EuMg2Bi2、EuP3等の磁気秩序構造や内場の磁場変化を測定する技術に躍進があった。④計算による状態密度や電場勾配と実験データとの比較、ベイズ推論によるデータの成分分離や実験の効率化に多大な可能性があることを示した。
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