Nonlinear current response of two-dimensional systems under in-plane magnetic field

TL;DR

This paper develops a comprehensive semiclassical theory for the nonlinear current response in two-dimensional systems under in-plane magnetic fields, revealing new contributions and providing experimental distinction methods.

Contribution

It introduces a unified theory including both longitudinal and transverse nonlinear currents, discovering a novel time-reversal-odd Hall current with geometric origin.

Findings

Identification of a new time-reversal-odd Hall current contribution.

Different symmetry and angular dependence of various current contributions.

Demonstration of the theory using the Rashba model.

Abstract

We theoretically investigate the nonlinear response current of a two-dimensional system under an in-plane magnetic field. Based on the extended semiclassical theory, we develop a unified theory including both longitudinal and transverse currents and classify contributions according to their scaling with the relaxation time. Besides time-reversal-even contributions, we reveal a previously unknown time-reversal-odd contribution to the Hall current, which occurs in magnetic systems, exhibits band geometric origin, and is linear in relaxation time. We show that the different contributions exhibit different symmetry characters, especially in their angular dependence on the field orientation, which can be used to distinguish them in experiment. The theory is explicitly demonstrated in the study of the Rashba model. Our work presents a deepened understanding of nonlinear planar transport, proposes approaches to distinguish different contributions, and sheds light on possible routes to enhance the effect in practice.