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

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.