Realizing intrinsic magnetic topological insulators with gapped topological surface states in MnBi<sub>2-x</sub>Sb<sub>x</sub>Te<sub>4</sub>

ORAL

Abstract

The interplay between magnetism and topology of materials could create a variety of exotic topological quantum states, including the quantum anomalous Hall (QAH) effect showing dissipationless chiral edge states, the topological axion states displaying quantized magnetoelectric effects, and Majorana fermions, obeying non-Abelian statistics. All of these quantum states are hopefully realizable in MnBi2Te4. However, the Fermi level is usually in the bulk conduction band of the materials, which is not ideal for revealing these topological properties in transport. Here we show that by doping MnBi2Te4 with Sb, the Fermi level can be shifted while the non-trivial topology is maintained. Scanning tunneling microscopy (STM) is utilized to observe electronic band structure by quasi-particle interference, which reveals surface states in the bulk band gap and a surface band gap at the Dirac point. The transport from multiprobe-STM further displays a surface dominant transport. Our results show that the MnBi2-xSbxTe4 is an intrinsic magnetic topological insulator that would offer an ideal platform to observe various exotic topological phenomena.

*This research was performed at the Center for Nanophase Materials Sciences which is a DOE Office of Science User Facility.

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Presenters

  • Wonhee Ko

    • Oak Ridge National Laboratory
    • Center for Nanophase Materials Sciences, Oak Ridge National Laboratory
    • Oak Ridge National Lab

Authors

  • Wonhee Ko

    • Oak Ridge National Laboratory
    • Center for Nanophase Materials Sciences, Oak Ridge National Laboratory
    • Oak Ridge National Lab

  • Marek Kolmer

    • Oak Ridge National Laboratory
    • Center for Nanophase Materials Sciences, Oak Ridge National Laboratory

  • Jiaqiang Yan

    • Materials Science and Engineering, The University of Tennessee
    • Oak Ridge National Lab
    • Oak Ridge National Laboratory
    • Materials Science and Technology Division, Oak Ridge National Laboratory
    • Materials Science and Technology Division, Oak Ridge National Lab
    • Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA

  • Anh Pham

    • Center for Nanophase Materials and Sciences, Oak Ridge National Laboratory
    • Center for Nanophase Materials Sciences, Oak Ridge National Laboratory
    • Oak Ridge National Lab

  • Mingming Fu

    • Center for Nanophase Materials Sciences, Oak Ridge National Laboratory

  • Felix Luepke

    • Center for Nanophase Materials Sciences, Oak Ridge National Laboratory

  • Satoshi Okamoto

    • Oak Ridge National Lab
    • Materials Science and Technology Division, Oak Ridge National Laboratory
    • University of Tennessee, Knoxville
    • Oak Ridge National Laboratory

  • Panchapakesan Ganesh

    • Center for Nanophase Materials and Sciences, Oak Ridge National Laboratory
    • Oak Ridge National Laboratory
    • Center for Nanophase Materials Sciences, Oak Ridge National Laboratory
    • Oak Ridge National Lab

  • Zheng Gai

    • Center for Nanophase Materials Sciences Oak Ridge National Laboratory Oak Ridge, TN 37831, USA
    • Center for Nanophase Materials Sciences, Oak Ridge National Laboratory
    • CNMS, Oak Ridge National Lab
    • Center for Nanophase Materials Sciences, Oak Ridge National Lab

  • An-Ping Li

    • Oak Ridge National Laboratory
    • Center for Nanophase Materials Sciences, Oak Ridge National Laboratory
    • Oak Ridge National Lab