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.
*We acknowledge support from the Eberly Research Fellows Program, ONR, and NSF-MIP/2DCC.
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Presenters
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Michelle Tomczyk
- Pennsylvania State University
- Department of Physics and Astronomy, University of Pittsburgh
- University of Pittsburgh