Our current research concerns quantum electron transport phenomena in mesoscopic and low-dimensional electron systems. Much of the study focuses on spin-related phenomena in  semiconductor devices. The experiment includes micro-fabrication of devices, low-noise electron transport measurement at cryogenic temperatures, and characterization of the observed phenomena.

Some recent projects in our group have explored: Nuclear spin effect in quantum Hall systems, Kondo effect in semiconductor quantum dots, Electron spin polarization in quantum point contacts, Spectroscopy and transport measurements on the surface of topological insulators.

News

2024.04.11 Our recent paper entitled "Molecular beam epitaxy of superconducting FeSeTe thin films interfaced with magnetic topological insulators" has been published in Physical Review Materials.

2023.12.30 Our recent paper entitled "Probing the edge states of Chern insulators using microwave impedance microscopy" has been published in Phys. Rev. B. This is a collaboration work with UC San Diego, Stanford University, RIKEN CEMS, and so on.

Selected Publications

Laughlin charge pumping in a quantum anomalous Hall insulator

Minoru Kawamura, Masataka Mogi, Ryutaro Yoshimi, Takahiro Morimoto, Kei S. Takahashi, Atsushi Tsukazaki, Naoto Nagaosa, Masashi Kawasaki, and Yoshinori Tokura

Nature Physics 19, 333-337 (2023). https://doi.org/10.1038/s41567-022-01888-2.

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

M. Mogi, Y. Okamura, M. Kawamura, R. Yoshimi, K. Yasuda, A. Tsukazaki, K. S. Takahashi, T. Morimoto, N. Nagaosa, M. Kawasaki, Y. Takahashi & Y. Tokura 

Nature Physics 18, 390-394 (2022). https://doi.org/10.1038/s41567-021-01490-y 

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

Yuma Okazaki, Takehiko Oe, Minoru Kawamura, Ryutaro Yoshimi, Shuji Nakamura, Shintaro Takada, Masataka Mogi, Kei S. Takahashi, Atsushi Tsukazaki, Masashi Kawasaki, Yoshinori Tokura, and Nobu-Hisa Kaneko

Nature Physics 18, 25–29 (2022). https://doi.org/10.1038/s41567-021-01424-8

Precise resistance measurement of quantum anomalous Hall effect in magnetic heterostructure film of topological insulator

Yuma Okazaki, Takehiko Oe, Minoru Kawamura, Ryutaro Yoshimi, Shuji Nakamura, Shintaro Takada, Masataka Mogi, Kei S. Takahashi, Atsushi Tsukazaki, Masashi Kawasaki, Yoshinori Tokura, and Nobu-Hisa Kaneko

 Applied Physics Letters 116, 143101 (2020).

Topological quantum phase transition in magnetic topological insulator upon magnetization rotation

Minoru Kawamura, Masataka Mogi, Ryutaro Yoshimi, Atsushi Tsukazaki, Yusuke Kozuka, Kei S. Takahashi, Masashi Kawasaki, and Yoshinori Tokura

Physical Review B 98, 140404(R) (2018).

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

M. Mogi, M. Kawamura, R. Yoshimi, A. Tsukazaki, Y. Kozuka, N. Shirakawa, K. S. Takahashi, M. Kawasaki, and Y. Tokura

Nature Materials 16, 516-521 (2017).

Please see also press release (Japanese).

Current-driven instability of quantum anomalous Hall effect in ferromagnetic topological insulator thin films

M. Kawamura, R. Yoshimi, A. Tsukazaki, K. S. Takahashi, M. kawasaki, and Y. Tokura

Physical Review Letters 119, 016803 (2017).

Electronic magnetization of a quantum point contact measured by nuclear magnetic resonance

Minoru Kawamura, Keiji Ono, Peter Stano, Kimitoshi Kono, and Tomosuke Aono,

Physical Review Letters 115, 036601 (2015). Selected as "Editor's suggestion".

This work has been highlightened in Nature Nanotechnology (Issueu 9, 2015).

Please see also press release (Japanese) and RIKEN Research.

Imaging the two-component nature of Dirac–Landau levels in the topological surface state of Bi2Se3

Ying-Shuang Fu, Minoru Kawamura, Kyushiro Igarashi, Hidenori Takagi, Tetsuo Hanaguri, and Takao Sasagawa,

Nature Physics 10, 815-819 (2014).

Please see also press release (Japanese) and RIKEN Research.

Resistive detection of nuclear spins in a single quantum dot under Kondo effect regime

Minoru Kawamura, Daniel Gottwald, Keiji Ono, Tomoki Machida, and Kimitoshi Kono

Physical Review B 87, 081303(R) (2013). Selected as "Editor's suggestion".

Spatial gradient of dynamic nuclear spin polarization induced by breakdown of quantum Hall effect

Minoru Kawamura, Kimitoshi Kono, Yoshiaki Hashimoto, Shingo Katsumoto, and Tomoki Machida

Physical Review B 83, 041305(R) (2011). Selected as "Editor's suggestion".

Momentum-resolved Landau-level spectroscopy of Dirac surface state in Bi2Se3

Tetsuo Hanaguri, Kyushiro Igarashi, Minoru Kawamura, Hidenori Takagi, and Takao Sasagawa

Physical Review B 82, 081305(R) (2010). Selected as "Physics" and "Editor's suggestion".

Strain-induced enhancement of electric quadrupole splitting in resistively detected nuclear magnetic resonance spectrum in quantum Hall systems

Minoru Kawamura, Tatsuya Yamashita, Hiroyuki Takahashi, Satoru Masubuchi, Yoshiaki Hashimoto, Shingo Katsumoto, and Tomoki Machida

Applied Physics Letters 96, 032102 (2010).

Dynamic nuclear polarization induced by breakdown of fractional quantum Hall effect

Minoru Kawamura, Masashi Ono, Yoshiaki Hashimoto, Shingo Katsumoto, Kohei Hamaya, and Tomoki Machida

Physical Review B 79, 193304 (2009).

Tunneling properties at the interface between superconducting Sr2RuO4 and a Ru micro-inclusion

Minoru Kawamura, Hiroshi Yaguchi, Naoki Kikugawa, Yoshiteru Maeno and Hideaki Takayanagi

J. Phys. Soc. Jpn. 74, pp. 531-534 (2005).