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arXiv · 2408.09543

Nonlinear planar magnetotransport as a probe of the topology of surface states

Maria Teresa Mercaldo·Mario Cuoco·Carmine Ortix
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Abstract

It has been recently established that transport measurements in the nonlinear regime can give direct access to the quantum metric (QM): the real part of the quantum geometric tensor characterizing the geometry of the electronic wavefunctions in a solid. In topological materials, the QM has been so far revealed in thin films of the topological antiferromagnet MnBi$_2$Te$_4$ where it provides a direct contribution to longitudinal currents quadratic in the driving electric field. Here we show that the Dirac surface states of strong three-dimensional topological insulators have a QM that can be accessed from the nonlinear transport characteristics in the presence of an externally applied planar magnetic field. A previously unknown intrinsic part of the longitudinal magnetoconductivity carries the signature of the QM while coexisting with the extrinsic part responsible for the so-called bilinear magnetoelectric resistance. We prove that the QM-induced nonlinear magnetotransport carries specific signatures of single Dirac cones. This allows to use it as an efficient diagnostic tool of the bulk topology of three-dimensional non-magnetic insulators.

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Maria Teresa Mercaldo, Mario Cuoco, Carmine Ortix. 2024-08-18. Nonlinear planar magnetotransport as a probe of the topology of surface states. https://doi.org/10.1103/physrevb.111.155442

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