Magnetochiral anisotropy on a quantum spin Hall edge

We develop a theory of nonlinear low-magnetic-field magnetotransport on a helical edge of a quantum spin Hall insulator due to the edge state coupling to bulk midgap states. We focus on the part of the nonlinear I-V characteristic that is odd in the applied magnetic field, and quadratic in the appli...

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Bibliographic Details
Published in:arXiv.org 2024-07
Main Authors: Chen, Youjian, Quaresima, Gary, Zhao, Wenjin, Elliott Runburg, Cobden, David, Pesin, D A
Format: Article
Language:English
Subjects:
Anisotropy
Bias
Current voltage characteristics
Magnetic fields
Nonlinearity
Online Access:Get full text
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Summary:We develop a theory of nonlinear low-magnetic-field magnetotransport on a helical edge of a quantum spin Hall insulator due to the edge state coupling to bulk midgap states. We focus on the part of the nonlinear I-V characteristic that is odd in the applied magnetic field, and quadratic in the applied bias voltage. This part of the I-V characteristic corresponds to the resistance of the sample being dependent on the relative orientation of the current and an external magnetic field, hence represents a type of edge magnetochiral anisotropy. We identify two mechanisms of the magnetochiral anisotropy. One is related to the Hubbard interaction on the midgap state, which leads to the dependence of the scattering characteristics on the current flowing on the edge, which results in bias-voltage-dependent resistance, or equivalently conductance, hence a nonlinear I-V. The other is related to the modification of the edge dispersion by a magnetic field, and requires nonlinearity in the edge dispersion. We compare the developed theory to the experiments on monolayer \(\mathrm{WTe}_{2}\), and find good agreement with the developed theory.
ISSN:2331-8422