Fabrication of periodic arrays of dislocations in topological insulators and investigation of their electronic properties

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K04984
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 26010:Metallic material properties-related
• Research Institution: The University of Tokyo
• Principal Investigator: Tokumoto Yuki 東京大学, 生産技術研究所, 講師 (20546866)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: トポロジカル絶縁体 / バルク絶縁体化 / 転位

Outline of Final Research Achievements

We plastically deformed Bi-Sb topological insulator and introduced dislocations which satisfy the condition for metallic gapless states. Then, we performed electrical conductivity measurements and succeeded in detecting remarkable effect of dislocation conduction.
Furthermore, we investigated surface conduction and scattering mechanism of surface electrons by using Pb-(Bi,Sb)-Te topological insulator with high bulk resistivity.
As for Pb-(Bi,Sb)-(Te,Se) topological insulator, we could not obtain higher bulk resistivity than Pb-(Bi,Sb)-Te topological insulator. However, we revealed that the semiconducting regions with higher resistivity are locally distributed.

Free Research Field

材料科学

Academic Significance and Societal Importance of the Research Achievements

本研究では、トポロジカル絶縁体の転位に局在した金属状態について、実験により定量的に検証することに成功した。この成果はトポロジカル絶縁体の転位に関する基礎および応用研究の推進に寄与するものである。
また、トポロジカル絶縁体の転位に局在した金属状態を、より高温で検出・観測可能な候補材料の開拓を行った。この成果は、トポロジカル絶縁体の転位だけでなく、表面伝導・表面状態の研究の推進にも寄与するものであり、さらに応用の可能性を広げることにつながる。