Coherent detection of the oscillating acoustoelectric effect in graphene

TL;DR

This paper demonstrates the coherent detection of the oscillating acoustoelectric effect in graphene using surface acoustic waves, revealing dynamic charge modulation and carrier redistribution through transport measurements.

Contribution

It introduces a method for directly detecting the oscillating component of the acoustoelectric effect in graphene via coherent rectification with electromagnetic waves.

Findings

Successful detection of oscillating acoustoelectric signals in graphene.

Frequency and gate dependence of rectified signals characterized.

Quantitative insights into carrier redistribution dynamics driven by SAWs.

Abstract

In recent years, surface acoustic waves (SAWs) have emerged as a novel technique for generating quasiparticle transport and band modulation in condensed matter systems. SAWs interact with adjacent materials through piezoelectric and strain fields, dragging carriers in the direction of wave propagation. Most studies on the acoustoelectric effect have focused on the collective directional motion of carriers, which generates a steady electric potential difference, while the oscillating component from dynamic spatial charge modulation has remained challenging to probe. In this work, we report the coherent detection of oscillating acoustoelectric effect in graphene. This is achieved through the coherent rectification of spatial-temporal charge oscillation with electromagnetic waves emitted by interdigital transducers. We systematically investigate the frequency and gate dependence of rectified signals and quantitatively probe the carrier redistribution dynamics driven by SAWs. The observation of oscillating acoustoelectric effect provides direct access to the dynamic spatial charge modulation induced by SAWs through transport experiments.