| Project/Area Number |
16H03999
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Condensed matter physics I
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| Research Institution | The University of Tokyo |
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Principal Investigator |
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| Research Collaborator |
ADACHI hirotoshi
UCHIDA kazuhito
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| Project Period (FY) |
2016-04-01 – 2019-03-31
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| Project Status |
Completed (Fiscal Year 2018)
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| Budget Amount *help |
¥17,420,000 (Direct Cost: ¥13,400,000、Indirect Cost: ¥4,020,000)
Fiscal Year 2018: ¥4,290,000 (Direct Cost: ¥3,300,000、Indirect Cost: ¥990,000)
Fiscal Year 2017: ¥4,290,000 (Direct Cost: ¥3,300,000、Indirect Cost: ¥990,000)
Fiscal Year 2016: ¥8,840,000 (Direct Cost: ¥6,800,000、Indirect Cost: ¥2,040,000)
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| Keywords | 物性実験 / 超薄膜 / トポロジー / 表面・界面物性 / トポロジカル絶縁体 / ワイル半金属 / 量子振動 / 次元交差 |
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| Outline of Final Research Achievements |
We have investigated the dimensional crossover effect when thinning a three-dimensional topological crystal into a two-dimensional atomic layer by observing the thickness dependence of magnetoresistance. In a layered Weyl semimetal, WTe2, the Fourier analysis of the Shubnikov-de Haas (SdH) oscillations of the magnetoresistance revealed that the SdH frequencies corresponding to the three-dimensional Fermi surfaces begin to decrease with thinning. Moreover, it was found that several weak subpeaks with two-dimensional behaviors appear in the low frequency side of each peak. These features can be understood in a unified manner as the dimensional crossover effect of the electronic structure, namely, splitting of three-dimensional bands into two-dimensional subbands by the quantum size effect.
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| Academic Significance and Societal Importance of the Research Achievements |
トポロジカル物質相は近年の物性物理学において急速に発展している分野の１つであり、エラー耐性の高い量子計算への応用可能性などから工学的にも注目されている。一方、トポロジカル相の発現は系の対称性と次元性に深く関係することが知られている。薄膜化により次元性を変えたときにトポロジカル相が示す次元交差現象の理解は、学術的に重要であるばかりでなく、薄膜化・微細化してデバイス応用する知見を得る上で応用上も重要である。本研究によりワイル半金属WTe2の薄膜化に伴う電子構造の次元交差を押さえることができた。
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