Acoustoelectric effect in two-dimensional Dirac materials exposed to Rayleigh surface acoustic waves

TL;DR

This paper investigates the acoustoelectric effect in two-dimensional Dirac materials under Rayleigh surface acoustic waves, analyzing current components and effects of substrate type on the phenomenon.

Contribution

It provides a detailed analysis of the acoustoelectric effect in 2D Dirac materials, highlighting the roles of valley warping, electron lifetime, and substrate type, which are novel insights.

Findings

Hall component of current depends on valley warping

Drift and diffusive currents are distinguished and their dominance analyzed

Rayleigh and Bluestein-Gulyaev waves have different effects on the current

Abstract

We study the acoustoelectric effect in two-dimensional materials like transition metal dichalcogenide monolayers located on a non-piezoelectric substrate and exposed to the Rayleigh surface acoustic waves. We investigate the behavior of the Hall component of the electric current density which appears due to the trigonal warping of the valleys in k-space. We calculate the spectrum of the current density and study its dependence on the electron effective lifetime and density in the sample. We distinguish between the drift and diffusive components of the current and show, which components turn out predominant. Furthermore, we compare the effect of the Rayleigh and Bluestein-Gulyaev acoustic waves, which appear if the sample is located on a piezoelectric substrate.