Quantum interference effect on the surface of topological insulators

2022 Fiscal Year Final Research Report

• Project/Area Number: 18H01155
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 13020:Semiconductors, optical properties of condensed matter and atomic physics-related
• Research Institution: Institute of Physical and Chemical Research
• Principal Investigator: Kawamura Minoru 国立研究開発法人理化学研究所, 創発物性科学研究センター, 専任研究員 (60391926)
• Project Period (FY): 2018-04-01 – 2023-03-31
• Keywords: トポロジカル絶縁体 / 量子異常ホール効果 / ラフリン電荷ポンプ / 電気磁気効果

Outline of Final Research Achievements

We investigated the effect of the geometrical phase on the electronic state of the surface of topological insulators through the measurement of macroscopic physical quantities called electrical transport measurements. In the originally planned experiments on quantum interference effects such as the Aharonov-Bohm effect, the inelastic scattering length was shorter than the sample size, so the interference effects could not be clearly measured. On the other hand, in the study of magnetic topological insulators doped with magnetic elements, it was shown that the Hall resistance of the quantum anomalous Hall effect, which is an effect of the geometrical phase of the electronic system, matches the quantum resistance value with an accuracy of eight orders of magnitude or more. Furthermore, we observed Laughlig charge pump phenomenon and showed that the hole conductivity quantized even in systems without end channels connecting the electrodes.

Free Research Field

物性物理学

Academic Significance and Societal Importance of the Research Achievements

量子異常ホール効果の精密測定では、ホール抵抗値が８桁以上の精度で量子化することを示した。この成果は量子異常ホール効果の学理を構築する上で重要な測定結果であると同時に、量子異常ホール効果を無磁場でも使える電気抵抗標準へ応用するための第一歩である。物質のトポロジーを積極的に利用した典型的な応用例であり、トポロジカル物質をの応用研究へ向けて弾みがつくことが期待できる。