2021 Fiscal Year Final Research Report
Growth of Heusler-type Weyl semimetal thin films on ferroelectric substrates and electric-field control of topological states
| Project/Area Number |
20K21002
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| Research Category |
Grant-in-Aid for Challenging Research (Exploratory)
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| Allocation Type | Multi-year Fund |
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| Review Section |
Medium-sized Section 21:Electrical and electronic engineering and related fields
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| Research Institution | Osaka University |
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Principal Investigator |
Yamada Shinya 大阪大学, 基礎工学研究科, 助教 (30725049)
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| Project Period (FY) |
2020-07-30 – 2022-03-31
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| Keywords | ホイスラー合金 / ワイル半金属 / 強誘電体 |
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| Outline of Final Research Achievements |
We attempted to fabricate thin films of a ferrimagnetic Heusler alloy, Ti2MnAl, on ferroelectric substrates by molecular beam epitaxy, where Ti2MnAl with an XA-ordered structure is theoretically predicted to be a Weyl semimetal. By using nonstoichiometric deposition conditions, epitaxial Ti2MnAl films with nearly stoichiometric composition were obtained. Although we measured magnetotransport properties of the epitaxial Ti2MnAl films, we could not observe magnetotransport properties peculiar to Weyl semimetal. From structural characterizations and magnetotransport properties, we considered that the improvement of structural ordering in the Ti2MnAl films is necessary for observing magnetotransport properties peculiar to Weyl semimetal. For Heusler-type spin-gapless material/ferroelectric heterostructures, we presented the possibility of electric-field control of magnetotransport properties.
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| Free Research Field |
電気電子材料
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| Academic Significance and Societal Importance of the Research Achievements |
本研究では，これまで材料探索・物性探索が中心であった材料群に対して，それらの特徴的な電子構造に起因した物性をゲート電圧制御する新技術の開発を目指した．最終目標としていたトポロジカル物質に特徴的な磁気輸送特性の電界制御までには至らなかったが，類似したバンド構造(スピンギャップレス半導体)を持つと予想されているホイスラー物質で検討を進め，電界で磁気輸送特性を制御できる可能性を見い出すことができた．今後，薄膜の結晶規則性を向上し，電界でトポロジカル状態のON/OFF制御を実証できれば，新しいスピントロニクス素子への応用の芽を創出することにつながると期待される．
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