2023 Fiscal Year Final Research Report
Elucidation of electronic structure and enhancement of thermopower in Heusler-type Weyl magnetic thin films
| Project/Area Number |
21K14540
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| Research Category |
Grant-in-Aid for Early-Career Scientists
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| Allocation Type | Multi-year Fund |
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| Review Section |
Basic Section 29020:Thin film/surface and interfacial physical properties-related
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| Research Institution | Hiroshima University (2023)
Japan Atomic Energy Agency (2021-2022) |
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Principal Investigator |
Sumida Kazuki 広島大学, 放射光科学研究センター, 特任助教 (20882369)
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| Project Period (FY) |
2021-04-01 – 2024-03-31
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| Keywords | ホイスラー合金 / ワイル磁性体 / 角度分解光電子分光 / スピン分解光電子分光 / 共鳴光電子分光 / ハーフメタル / 異常ネルンスト効果 / スピン・角度分解光電子分光 |
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| Outline of Final Research Achievements |
In this work, we focussed on Co-based Heusler alloy thin films exhibiting giant thermopower and investigated their electronic structures by using various photoelectron spectroscopies. First, we performed soft x-ray angle-resolved photoelectron spectroscopy (ARPES) on Co2MnGa thin films, which show the largest thermopower among ferromagnets at room temperature and zero-field, and successfully observed the topologically nontrivial bulk electronic structure. Resonant photoelectron spectroscopy was performed on a Weyl ferromagnet candidate Co2FeSi thin film. Our findings revealed the role of electron correlation effects in Co2FeSi. For Co2MnSi thin film, which is predicted to be a half-metallic ferromagnet, we performed spin-resolved ARPES using vacuum ultraviolet synchrotron radiation and found that thermally excited magnons play an important role in the spin depolarization mechanism.
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| Free Research Field |
固体物性
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| Academic Significance and Societal Importance of the Research Achievements |
本研究によって、ワイル磁性体が持つ特殊な電子構造と巨大熱輸送特性の対応関係を解明することに成功した。現在、室温・ゼロ磁場で得られているワイル磁性体の熱電能は実用環境発電に応用するには今一歩及ばないが、本研究を通して得られた成果が熱電能の更なる向上に寄与することが期待される。また、異常ネルンスト効果のみならず、ハーフメタル性、電子相関効果などこれまで未解明となってきたCo基ホイスラー合金の基礎特性に関する知見も得ることができたため、その学術的意義は大きい。
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