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Realisation of Wide Bandgap Quantum Anomalous Hall Insulator in Ultra-thin MnBi<sub>2</sub>Te<sub>4 </sub>and Bi<sub>2</sub>Te<sub>3 </sub>Heterostructures

ORAL

Abstract

Interfacing ferromagnetic insulators with 3D topological insulators offers the potential to engineer heterostructures that can host the Quantum Anomalous Hall (QAH) insulator and Topological Magnetoelectric effect phases. These phases are realised as a result of magnetisation that breaks time reversal symmetry and opens up an exchange gap. Single septuple layer (SL) of MnBi2Te4 (MBT) has recently been reported to be a 2D ferromagnetic insulator possessing a bandgap >700 meV with long-range ferromagnetic order.1 Its chemical and structural similarity to the 3D topological insulator Bi2Te3, has led to predictions that MBT/BT/MBT heterostructures may yield robust QAH insulator phases with bandgaps >50 meV.2 Here we demonstrate the growth of 1SL MnBi2Te4 and 4QL Bi2Te3 heterostructures via MBE, and probe the electronic structure using angle resolved photoelectron spectroscopy. We observe massive Dirac Fermions with band gaps >50meV and strong hexagonal warping of the Dirac cone, in excellent agreement with theory. The engineering of massive Dirac Fermions and the QAH insulator phase in MBT/BT/MBT heterostructures has potential applications in spintronics and quantum computing.
1 Trang et al., arXiv:2009.06175
2 Otrokov et al., 2D Mater. 4, 025082 (2017)

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Presenters

  • Qile Li

    School of Physics and Astronomy, Monash University, Department of Materials Science And Engineering, Monash University

Authors

  • Qile Li

    School of Physics and Astronomy, Monash University, Department of Materials Science And Engineering, Monash University

  • Chi Xuan Trang

    School of Physics and Astronomy, Monash University

  • Weikang Wu

    Research Laboratory for Quantum Materials, Singapore University of Technology and Design, Division of Engineering Product Development, Singapore University of Technology and Design, Singapore University of Technology and Design

  • Jinwoong Hwang

    Advanced Light Source, Lawrence Berkeley National Laboratory

  • Sung-Kwan Mo

    Lawrence Berkeley National Laboratory, Advanced Light Source, Lawrence Berkeley National Laboratory, Advanced Light Source

  • Nikhil V. Medhekar

    Department of Materials Science and Engineering, Monash University, Department of Materials Science and Engineering, Monash Univerity, Department of Materials Science And Engineering, Monash University, Monash University

  • Shengyuan Yang

    Research Laboratory for Quantum Materials, Singapore University of Technology and Design, Division of Engineering Product Development, Singapore University of Technology and Design, Singapore University of Technology and Design

  • Mark T Edmonds

    Monash University, School of Physics and Astronomy, Monash University