Dirac electronic states of Bi<sub>2</sub>Se<sub>3</sub> thin films on ferromagnetic Cr<sub>2</sub>Si<sub>2</sub>Te<sub>6</sub> studied by high-resolution ARPES

ORAL

Abstract

We have epitaxially fabricated Bi2Se3 thin films on van der Waals ferromagnet, Cr2Si2Te6 (CST), and investigated their electronic structure by high-resolution angle-resolved photoemission spectroscopy (ARPES) [1]. We observed a large energy gap at the Dirac point in 2 quintuple-layer (QL) Bi2Se3 on CST in contrast to the gapless Dirac-cone state in 6 QL Bi2Se3 on CST. Compared to 2 QL Bi2Se3 on Si substrate, we found that the Dirac point of 2 QL Bi2Se3 on CST is located at lower binding energy with enhanced gap magnitude. In this talk, we will show temperature dependence of band structure across TC of CST, and discuss the origin of modulation of Dirac electronic states in Bi2Se3/CST heterostructure in terms of the lattice strain effect, interfacial coupling, and magnetic proximity effect.
[1] T. Kato et al., Phys. Rev. Mater. 4, 084202 (2020).

*This work was supported by Grant-in-Aid for Scientific Research on Innovative Areas “Topological Materials Science” (15H05853, 18H04215, and 15K21717), “J-Physics” (18H04311), JST-CREST (MJCR18T1), JST-PRESTO (MJPR18L7), JSPS KAKENHI (17H01139, 18H01821, 15H02105, 26287071, 19H02424, 19K22124, 19H05600, and 25287079), Electrotechnology of Chubu, WPI-AIMR, and GP-Spin at Tohoku University.

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Presenters

  • Takemi Kato

    • Department of Physics, Tohoku University

Authors

  • Takemi Kato

    • Department of Physics, Tohoku University

  • Katsuaki Sugawara

    • Department of Physics, Tohoku University

  • Naohiro Ito

    • Department of Physics, Tohoku University

  • Kunihiko Yamauchi

    • Institute of Scientific and Industrial Research, Osaka University

  • Takumi Sato

    • Department of Physics, Tohoku University

  • Tamio Oguchi

    • Osaka Univ
    • Institute of Scientific and Industrial Research, Osaka University

  • Takashi Takahashi

    • Department of Physics, Tohoku University

  • Yuki Shiomi

    • Department of Basic Science, University of Tokyo

  • Eiji Saitoh

    • Tohoku University
    • The University of Tokyo
    • Department of Applied Physics, The University of Tokyo
    • Department of Applied Physics, University of Tokyo

  • Takafumi Sato

    • Department of Physics, Tohoku University