Third-order Hall effect in the surface states of a topological insulator

TL;DR

This paper investigates the third-order Hall effect in the surface states of topological insulators, showing how tilt, warping, and doping influence the response, which can be experimentally verified and offers tunability.

Contribution

It demonstrates the existence and tunability of the third-order Hall effect in topological insulator surface states using semiclassical analysis.

Findings

Response magnitude increases with tilt and warping.

Chemical doping affects the third-order Hall response.

Third-order Hall can be the leading response in these systems.

Abstract

Time reversal and inversion symmetric materials fail to yield linear and nonlinear responses since they possess net zero Berry curvature. However, higher-order Hall response can be generated in these systems upon constraining the crystalline symmetries. Motivated by the recently discovered third-order Hall (TOH) response mediated by Berry connection polarizability, namely, the variation the Berry connection with respect to an applied electric field, here we investigate the existence of such Hall effect in the surface states of hexagonal warped topological insulator (e.g., Bi$_2$Te$_3$) under the application of electric field only. Using the semiclassical Boltzmann formalism, we investigate the effect of tilt and hexagonal warping on the Berry connection polarizability tensor and consequently, the TOH effect provided the Dirac cone remains gapless. We find that the magnitude of the response increases significantly with increasing the tilt strength and warping and therefore, they can provide the tunability of this effect. In addition, we also explore the effect of chemical doping on TOH response in this system. Interestingly, we show based on the symmetry analysis, that the TOH can be the leading-order response in this system which can directly be verified in experiments.