Investigating dissipation in the quantum anomalous Hall effect

ORAL

Abstract

In the quantum anomalous Hall effect, a magnetic exchange gap in a 3D topological insulator gives rise to dissipationless chiral edge states. Though the effect has recently been realized in a family of ferromagnetically-doped (Bi,Sb)$_2$Te$_3$ topological insulator thin films, experiments to date have found non-vanishing longitudinal resistance, contrary to initial theoretical expectations. Proposed sources of this dissipation include extra gapless or activated quasi-helical edge states, thermally activated 2D conduction, and variable-range hopping. Here, we discuss transport measurements of Corbino disk and non-local geometries to identify the mechanism of non-ideal behavior.

*This work supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, under Award No. 19-7503.

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Authors

  • Eli Fox

    • Stanford University

  • Andrew Bestwick

    • Stanford University

  • David Goldhaber-Gordon

    • Stanford University

  • Yang Feng

    • Tsinghua University

  • Yunbo Ou

    • Tsinghua University

  • Ke He

    • Tsinghua University

  • Yayu Wang

    • Tsinghua University

  • Qi-kun Xue

    • Tsinghua University

  • Xufeng Kou

    • University of California, Los Angeles

  • Lei Pan

    • University of California, Los Angeles

  • Kang Wang

    • University of California, Los Angeles