Rayleigh surface wave interaction with 2D exciton Bose-Einstein condensate

TL;DR

This paper investigates how Rayleigh surface acoustic waves interact with a 2D exciton Bose-Einstein condensate on a semiconductor surface, analyzing attenuation and velocity changes across the phase transition.

Contribution

It provides a detailed theoretical analysis of SAW interaction with excitonic BEC, considering both deformation potential and piezoelectric mechanisms, and explores temperature-dependent effects.

Findings

SAW attenuation and velocity are significantly different below and above the BEC critical temperature.

The interaction mechanisms depend on frequency and exciton density.

Distinct signatures of BEC phase transition are observed in SAW properties.

Abstract

We describe the interaction of the Rayleigh surface acoustic wave (SAW) traveling on the semiconductor substrate and interacting with excitonic gas in a double quantum well located on the substrate surface. We study the SAW attenuation and its velocity renormalization due to coupling with excitons. Both the deformation potential and piezoelectric mechanisms of the SAW-exciton interaction are considered. We focus our attention on the frequency and excitonic density dependencies of the SAW absorption coefficient and velocity renormalization at temperatures both above and well below the critical temperature of Bose-Einstein condensation of excitonic gas. We demonstrate that the SAW attenuation and velocity renormalization are strongly different below and above the critical temperature.