Superconducting Proximity Effect in Magnetically-Doped Topological Insulators using Bulk Single Crystals

ORAL

Abstract

Superconducting proximity effect on magnetic topological insulators (TIs) is expected to induce unconventional superconductivity, some of which can host the Majorana fermion. Recently, we observed some unusual behaviors on Nb/Fe-doped TI/ Nb Josephson junctions: e.g., a unique three-peak structure and a 4π-periodic Josephson current. However, those origins are still under debate due to possible contributions from the bulk and the edge modes to the proximity effect.
In this study, we prepared another magnetic TI with a high bulk resistivity and fabricated its Josephson junctions without edge contacts. As a result, a similar three-peak structure was also observed, suggesting that the observed unique behaviors found in the former junction also came from the surface contribution. Furthermore, we observed a unique magnetic response possibly related to bulk magnetic properties. We believe that those results promote our understanding of the proximity effect on topological materials.

*This study was supported by JST CREST (Grant No. JPMJCR16F2) and KAKENHI (Grant Nos. JP15H05851, 15H05853, 16H03847, and 18H01243). Crystal growth was supported by the CRP of MSL-Tokyo Tech. The fabrication process was performed at the AIST-NPF, supported by NTPJ of the MEXT, Japan.

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Presenters

  • Rikizo Yano

    • Applied Physics, Nagoya University

Authors

  • Rikizo Yano

    • Applied Physics, Nagoya University

  • Kohei Tsumura

    • Applied Physics, Nagoya University

  • Hishiro T. Hirose

    • Laboratory for Materials and Structures, Tokyo Institute of Technology

  • Masahiro Yamamoto

    • Applied Physics, Nagoya University

  • Andrei Kudriashov

    • TQPSS, Moscow Institute of Physics and Technology

  • Masao Koyanagi

    • National Institute of Advanced Industrial Science and Technology

  • Hiromi Kashiwaya

    • National Institute of Advanced Industrial Science and Technology

  • Yasuhiro Asano

    • Center of Topological Science and Technology, Hokkaido University

  • Vasily Stolyarov

    • TQPSS, Moscow Institute of Physics and Technology

  • Takao Sasagawa

    • Tokyo Inst. of Tech.
    • Laboratory for Materials and Structures, Tokyo Institute of Technology

  • Satoshi Kashiwaya

    • Applied Physics, Nagoya University