Tuning Chern Number in Quantum Anomalous Hall Insulators

ORAL

Abstract

The quantum anomalous Hall (QAH) effect is a two-dimensional topological insulating state that has quantized Hall resistance of h/Ce2 and vanishing longitudinal resistance under zero external magnetic field, where C is called Chern number. Up to now, the zero magnetic field QAH effect has been realized only for C = 1. Here we used molecular beam epitaxy to fabricate magnetic TI multilayers and realized the well-defined QAH effect with tunable Chern number up to 5. We further demonstrated that in the same multilayer configuration, the Chern number can be tuned by varying either the Cr doping level or the thickness of the interior magnetic TI layer. One theoretical model is developed to explain our experimental observations and establish the phase diagram for the QAH effect with the tunable Chern number. Our results facilitate the applications of dissipationless chiral edge currents in energy-efficient electronic devices and open the possibility for developing multi-channel quantum computing and high-capacity chiral circuit interconnects.

*This work is supported by DOE grant (DE-SC0019064), ARO (W911NF1810198), and the Gordon and Betty Moore Foundation’s EPiQS Initiative (Grant GBMF9063 to C.Z.C.).

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Presenters

  • Yifan Zhao

    • Pennsylvania State University
    • Department of Physics, Pennsylvania State University

Authors

  • Yifan Zhao

    • Pennsylvania State University
    • Department of Physics, Pennsylvania State University

  • Ruoxi Zhang

    • Pennsylvania State University

  • Ruobing Mei

    • Pennsylvania State University

  • Ling-Jie Zhou

    • Pennsylvania State University

  • Hemian Yi

    • Pennsylvania State University
    • Department of Physics, Pennsylvania State University

  • Ya-Qi Zhang

    • Pennsylvania State University

  • Jiabin Yu

    • Pennsylvania State University
    • Condensed Matter Theory Center, Department of Physics, University of Maryland, College Park

  • Run Xiao

    • Pennsylvania State University
    • Physics, Pennsylvania State University

  • Ke Wang

    • Pennsylvania State University
    • Materials Research Institute, The Pennsylvania State University

  • Nitin Samarth

    • Pennsylvania State University
    • Department of Physics, The Pennsylvania State University
    • Physics, The Pennsylvania State University
    • Physics, Pennsylvania State University
    • The Pennsylvania State University

  • Moses H W Chan

    • Pennsylvania State University
    • Department of Physics, The Pennsylvania State University

  • Chaoxing Liu

    • The department of Physics, Pennsylvania State University
    • Pennsylvania State University
    • Department of Physics, the Pennsylvania State University, University Park

  • Cui-Zu Chang

    • Pennsylvania State University
    • Department of Physics, The Pennsylvania State University
    • Department of Physics, Pennsylvania State University
    • The Pennsylvania State University