| 研究課題/領域番号 |
22KJ1151
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| 補助金の研究課題番号 |
22J23068 (2022)
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| 研究種目 |
特別研究員奨励費
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| 配分区分 | 基金 (2023)
補助金 (2022) |
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| 応募区分 | 国内 |
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| 審査区分 |
小区分13030:磁性、超伝導および強相関系関連
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| 研究機関 | 東京大学 |
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研究代表者 |
YU Tonghua 東京大学, 工学系研究科, 特別研究員(DC1)
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| 研究期間 (年度) |
2023-03-08 – 2025-03-31
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| 研究課題ステータス |
交付 (2023年度)
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| 配分額 *注記 |
2,500千円 (直接経費: 2,500千円)
2024年度: 800千円 (直接経費: 800千円)
2023年度: 800千円 (直接経費: 800千円)
2022年度: 900千円 (直接経費: 900千円)
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| キーワード | Electrides / Topological phases / Majorana Fermions / Half-Heuslers / Weyl semimetals / Topological materials / Magnetism / Molecular crystals / Ab initio calculations |
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| 研究開始時の研究の概要 |
This research aims to deepen our fundamental understanding of unique properties of electrides, a distinct family of materials where some electrons reside at interstitial space, and meanwhile implement electrides as a testbed for novel theories and methods, through which we hope to advance our predictive capability of this kind of notable materials.
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| 研究実績の概要 |
We mainly worked on the topological electronic properties of half-Heuslers with first-principles calculations, as well as in collaboration with experiments. Half-Heuslers go under the family of electrides owing to the vacancy site per unit cell.
1. We investigated the topological boundary states at the half-Heusler interfaces. In contrast to bare surface, we uncovered that the topological interfacial states are free from dangling bonds, and show higher flexibility of tuning. We found a quantum anomalous Hall state at the GdNiSb/LuPtBi interface, which was shown to support chiral Majorana modes due to the superconductivity of LuPtBi. This work paves the avenue for topological superconductivity at the half-Heusler interfaces.
2. We studied the colossal magnetoresistance (CMR) in half-Heuslers RAuSn (R, rare earth) in collaboration with experimentalists. For the experimentally observed CMR, we calculated the electronic band structure, revealing the Lifshitz transition (emergence of Weyl points) in RAuSn as the external magnetic field is applied. On top of that, we found that the CMR could be attributed to the spin-momentum locking generated by these field-induced Weyl points, as shown by the calculated Berry curvature and spin-resolved Fermi surfaces.
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| 現在までの達成度 (区分) |
現在までの達成度 (区分)
2: おおむね順調に進展している
理由
The research on the topological and magnetic properties of electrides has advanced as expected, with a primary focus on half-Heusler systems. We have identified the potential of topological half-Heuslers as platforms for chiral Majorana modes, which could be instrumental in the development of topological quantum computations. A manuscript on these findings is under preparation. In addition, we have studied the field-induced Weyl points in the half-Heusler compound HoAuSn and their role in the phenomenon of giant negative magnetoresistance. Our work on additional half-Heusler compounds in this series is ongoing, in collaboration with experimental research teams. We look forward to obtaining more significant results in the near future.
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| 今後の研究の推進方策 |
We will investigate the superconductivity of electrides, specifically focusing on the role of interstitial electrons. Some electrides exhibit superconductivity, particularly under pressure, yet the contribution of interstitial electrons to this phenomenon remains unclear. We aim to explore this using first-principles calculations.
Additionally, we will study the colossal negative magnetoresistance in half-Heuslers RAuSn (R: rare earth), expanding our research beyond R=Ho to uncover the universal mechanisms at play. This investigation will be conducted in collaboration with experimentalists.
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