Emerging nonlinear Hall effect in Kane-Mele two-dimensional topological insulators

TL;DR

This paper proposes a mechanism for the nonlinear Hall effect in Kane-Mele 2D topological insulators caused by symmetry breaking and demonstrates its connection to topological phase transitions, expanding understanding of nonlinear responses in topological materials.

Contribution

It introduces a new mechanism for the nonlinear Hall effect in Kane-Mele insulators involving symmetry breaking and external field tuning, linking it to topological phase transitions.

Findings

Nonlinear Hall effect arises from symmetry breaking in Kane-Mele insulators.

External electromagnetic fields can tune the energy gaps and influence the Hall effect.

Signatures of topological phase transitions are observable through the nonlinear Hall response.

Abstract

The recent observations of nonlinear Hall effect in time-reversal symmetry protected systems and on the surface of three-dimensional topological insulators due to an in-plane magnetic field have attracted immense experimental and theoretical investigations in two-dimensional transition metal dichalcogenides and Weyl semimetals. The origin of this type of second order effect has been attributed to the emergence of a Berry curvature dipole, which requires a low-symmetry environment. Here, we propose a mechanism for generating such a second order nonlinear Hall effect in Kane-Mele two-dimensional topological insulators due to spatial and time reversal symmetry breaking in the presence of Zeeman and Rashba couplings. By actively tuning the energy gaps with external electromagnetic fields we also demonstrate that the nonlinear Hall effect shows remarkable signatures of topological phase transitions existing in the considered two-dimensional systems.