Topological Electronics Research Team

Principal Investigator

PI Name
Minoru Kawamura
Title
Team Director
Brief Resume
2001 Ph. D., The University of Tokyo
2001 Research Associate, NTT Basic Research Laboratories
2003 Special Postdoctoral Researcher, Low Temperature Physics Laboratory, RIKEN
2006 Assistant Professor, Institute of Industrial Science, The University of Tokyo
2008 Research Scientist, Low Temperature Physics Laboratory, RIKEN
2015 Senior Research Scientist, Strong Correlation Quantum Transport Research Team, RIKEN Center for Emergent Matter Science
2024 Team Leader, Topological Electronics Research Team, RIKEN Center for Emergent Matter Science (-present)
Position name has been changed to Team Director as of April1, 2025

Outline

Our team studies quantum transport phenomena in solids. Using thin-film crystals of materials with strong spin-orbit interactions or materials with nontrivial topology in their band structures, we fabricate devices in which electronic correlations and geometrical phases play important roles, and measure electrical transport properties under extreme environments such as low temperatures and strong magnetic fields. Through these studies, we aim to discover new quantum phenomena that will expand our understanding of condensed matter physics, and to explore electronic and spintronic functions that utilize them, opening the door to new technologies.

Research Fields

Physics, Engineering, Materials Sciences

Keywords

Topological insulators
Topological superconductors
Thin films and interfaces
Quantum transport phenomena
Anomalous Hall effect

Results

Development of quantum resistance standard devices using magnetic topological insulators

Topological insulators are a group of materials that have insulating interiors and metallic surface states. In magnetic topological insulators doped with magnetic elements, the resistance perpendicular to the current (Hall resistance) becomes the quantum unit of electrical resistance, the von Klitzing constant (h/e2, where h is Planck’s constant and e is the elementary charge). This phenomenon known as the quantum anomalous Hall effect occurs even in the absence of an external magnetic field. Therefore, it is expected to work as a new type of quantum resistance standard that does not require a strong magnetic field. We have fabricated high-quality magnetic topological insulator heterostructure thin films by molecular beam epitaxy and confirmed that the Hall resistance value matches the von Klitzing constant with an accuracy of eight digits. It is expected that the elimination of the need for a strong magnetic field will lead to the miniaturization of quantum resistance standards.

(Left) Schematic illustration of the quantum anomalous Hall effect device. (Right) Temperature dependence of the longitudinal (Rxx) and Hall (Ryx) resistance.

Members

Minoru Kawamura

Team Director

Ryo Ogawa

Research Scientist

Yuki Sato

Postdoctoral Researcher

Publications

  1. M. Kawamura, M. Mogi, R. Yoshimi, T. Morimoto, K. S. Takahashi, A. Tsukazaki, N. Nagaosa, M. Kawasaki, and Y. Tokura

    Laughlin charge pumping in a quantum anomalous Hall insulator

    Nat. Phys. 19, 333–337 (2023)
  2. M. Mogi, Y. Okamura, M. Kawamura, R. Yoshimi, K. Yasuda, A. Tsukazaki, K. S. Takahashi, T. Morimoto, N. Nagaosa, M. Kawasaki, Y. Takahashi, and Y. Tokura

    Experimental signature of the parity anomaly in a semi-magnetic topological insulator

    Nat. Phys. 18, 390–394 (2022)
  3. Y. Okazaki, T. Oe, M. Kawamura, R. Yoshimi, S. Nakamura, S. Takada, M. Mogi, K. S. Takahashi, A. Tsukazaki, M. Kawasaki, Y. Tokura, and N.-H. Kaneko

    Quantum anomalous Hall effect with a permanent magnet defines a quantum resistance standard

    Nat. Phys. 18, 25 (2022)
  4. M. Kawamura, M. Mogi, R. Yoshimi, A. Tsukazaki, Y. Kozuka, K. S. Takahashi, M. Kawasaki, and Y. Tokura

    Topological quantum phase transition in magnetic topological insulator upon magnetization rotation

    Phys. Rev. B 98, 140404 (2018)
  5. M. Mogi, M. Kawamura, R. Yoshimi, A. Tsukazaki, Y. Kozuka, N. Shirakawa, K. S. Takahashi, M. Kawasaki, and Y. Tokura

    A magnetic heterostructure of topological insulators as a candidate for an axion insulator

    Nat. Mater. 16, 516 (2017)

Articles

Contact Us

2-1 Hirosawa, Wako, Saitama 351-0198 Japan

E-mail:
minoru[at]riken.jp