Electron Dynamics Reconstruction and Nontrivial Transport by Acoustic Waves

TL;DR

This paper develops a semiclassical framework to understand electron dynamics under surface acoustic waves, explaining experimental observations and predicting novel transport phenomena like acousto-electric Hall effects in 2D materials.

Contribution

It introduces a new semiclassical approach that accounts for non-uniform Brillouin zone effects, enabling better understanding of SAW-driven electron transport and related Hall effects.

Findings

Explains DC drag current observed experimentally.

Predicts acousto-electric Hall effect and other anomalous transport phenomena.

Proposes angular-dependent Hall effect as a probe for Berry curvature.

Abstract

Surface acoustic waves (SAWs) become a popular driving source in modern condensed matter physics, but most existing theories simplify them as electric fields and ignore the non-uniform Brillouin zone folding effect. We develop a semiclassical framework and reconstruct the electron dynamics by treating SAW as a quasi-periodic potential modulating electronic momentum distribution. This framework naturally explains the experimentally observed DC drag current and predicts acousto-electric Hall effect. The theory further reveals various SAW-driven transport phenomena, emerging anomalous Hall, thermal Hall, and Nernst effects within time-reversal symmetric systems. Illustrated in bilayer graphene and $\mathrm{MX_2}$ (M = Mo, W; X = S, Se, Te), the angular-dependent acousto-electric Hall effect provides an experimental probe for Berry curvature distribution.