Electrical control of intrinsic nonlinear Hall effect in antiferromagnetic topological insulator sandwiches

TL;DR

This paper proposes an electric field method to significantly enhance the nonlinear Hall effect in antiferromagnetic topological insulators by breaking PT symmetry, enabling controllable electronic properties.

Contribution

It introduces a mechanism for electric control of NHE by breaking PT symmetry, supported by a model of antiferromagnetic topological insulator sandwiches.

Findings

Enhanced NHE via PT symmetry breaking with electric fields

Lifting spin degeneracy in Kramers' pairs increases NHE contributions

Model demonstrates controllable NHE in topological insulator structures

Abstract

Nonlinear Hall effect (NHE) can originate from the quantum metric mechanism in antiferromagnetic topological materials with PT symmetry, which has been experimentally observed in MnBi2Te4. In this work, we propose that breaking PT symmetry via external electric fields can lead to a dramatic enhancement of NHE, thus allowing for an electric control of NHE. Microscopically, this is because breaking PT symmetry can lift spin degeneracy of a Kramers' pair, giving rise to additional contributions within one Kramers' pair of bands. We demonstrate this enhancement through a model Hamiltonian that describes an antiferromagnetic topological insulator sandwich structure.