Quantum Nonlinear Acoustic Hall Effect and Inverse Acoustic Faraday Effect in Dirac Insulators

TL;DR

This paper predicts a quantized nonlinear topological acoustoelectric response in Dirac insulators, enabling potential room-temperature acoustic devices by leveraging intrinsic valley-contrasting band topology.

Contribution

It introduces a novel mechanism for realizing quantum nonlinear Hall and inverse Faraday effects via acoustic waves in Dirac insulators, emphasizing intrinsic topological properties.

Findings

The effects are proportional to the quantized valley Chern number.

The response is independent of quasiparticle lifetime.

Static magnetization scales with acoustic frequency and strain-induced charge density.

Abstract

We propose to realize the quantum nonlinear Hall effect and the inverse Faraday effect through the acoustic wave in a time-reversal invariant but inversion broken Dirac insulator. We focus on the acoustic frequency much lower than the Dirac gap such that the interband transition is suppressed and these effects arise solely from the intrinsic valley-contrasting band topology. The corresponding acoustoelectric conductivity and magnetoacoustic susceptibility are both proportional to the quantized valley Chern number and independent of the quasiparticle lifetime. The linear and nonlinear components of the longitudinal and transverse topological currents can be tuned by adjusting the polarization and propagation directions of the surface acoustic wave. The static magnetization generated by a circularly polarized acoustic wave scales linearly with the acoustic frequency as well as the strain-induced charge density. Our results unveil a quantized nonlinear topological acoustoelectric response of gapped Dirac materials, like hBN and transition-metal dichalcogenide, paving the way toward room-temperature acoustoelectric devices due to their large band gaps.