Anisotropic magnetotransport and planar Hall effect in the quantum anomalous Hall regime

ORAL

Abstract

Perturbations to the metallic surface states of topological insulators (TIs) through interactions with magnetism or superconductivity can result in novel phenomena. For example, magnetically-doped TIs realize the theoretically-predicted quantum anomalous Hall (QAH) insulator, in which the surface states are gapped while current is carried in quantized chiral edge states even in zero magnetic field. Understanding the transition between the QAH insulator and dissipative metallic conduction regimes is of fundamental importance. We study this transition by measuring electrical transport while rotating an external magnetic field in different planes relative to the surface. Using scaling plots of the Hall and longitudinal conductance, we find an equivalency in the phase transition created by either rotating the field in the perpendicular plane or by increasing the temperature. Additionally, the angle-dependent in-plane transverse magnetoresistance, the planar Hall effect, exhibits anomalous behavior when perturbed by a small out-of-plane magnetic field. We interpret these observations in terms of the interplay between magnetization, dissipation-free chiral edge states, and dissipative surface states.

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Presenters

  • Michelle Tomczyk

    Pennsylvania State University, Department of Physics and Astronomy, University of Pittsburgh, University of Pittsburgh

Authors

  • Michelle Tomczyk

    Pennsylvania State University, Department of Physics and Astronomy, University of Pittsburgh, University of Pittsburgh

  • Di Xiao

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

  • Cui-Zu Chang

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

  • Anthony R. Richardella

    Pennsylvania State University, Materials Research Institute, Pennsylvania State University, Department of Physics and Materials Research Institute, Pennsylvania State University

  • Chao-Xing Liu

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

  • Nitin Samarth

    Department of Physics and Materials Research Institute, Pennsylvania State University, Physics, Penn State University, Physics, The Pennsylvania State University, Pennsylvania State University, Department of Physics, Pennsylvania State University, Materials Research Institute, Pennsylvania State University, Department of Physics, The Pennsylvania State University, Physics, Pennsylvania State University