Extrinsic nonlinear acoustic valley Hall effect in the massive Dirac materials

TL;DR

This paper explores both intrinsic and extrinsic contributions to the nonlinear acoustic valley Hall effect in 2D massive Dirac materials, revealing that extrinsic mechanisms can dominate in disordered monolayer MoS2, expanding understanding of valleytronics phenomena.

Contribution

It introduces the analysis of extrinsic contributions to nonlinear AVHE in 2D Dirac materials, highlighting their dominance in disordered systems, which was previously unexplored.

Findings

Extrinsic effects can induce a pure nonlinear AVHE.

Extrinsic mechanisms dominate in disordered monolayer MoS2.

Intrinsic contributions alone are insufficient to explain nonlinear AVHE in disordered systems.

Abstract

The nonlinear acoustic valley Hall effect (AVHE), a recently discovered novel acoustically driven phenomena, has sparked extensive interests in valleytronics. So far, only the intrinsic contributions from band structure (Berry curvature or asymmetric energy dispersions) to nonlinear AVHE have been investigated. Here, we theoretically investigate the nonlinear AVHE from both intrinsic and extrinsic contributions in two-dimensional (2D) hexagonal massive Dirac materials with disorders based on the Boltzmann formalism and also concretely analyse the behaviours of nonlinear AVHE in disordered monolayer MoS2. It's found that the extrinsic contributions (side jump and skew scattering) can also give rise to a pure nonlinear AVHE in the 2D hexagonal massive Dirac materials. Remarkably, the extrinsic mechanisms dominate the nonlinear AVHE in the disordered monolayer MoS2.