Numerical simulations of the polariton kinetic energy distribution in GaAs quantum-well microcavity structures

Abstract

Recent experiments have shown that polaritons in microcavities behave like a Bose-Einstein condensate above a critical density threshold and at low temperature. The polaritons are not in full equilibrium, however, due to particle decay and streaming in of generated particles from high-energy states. In this paper we present a full simulation of the thermalization of polariton and exciton populations, including polariton-polariton and exciton-exciton scattering, phonon emission and absorption, and polariton scattering with free electrons. We find that we can obtain good fits over a wide range of polariton densities. The fits imply that the enhancement of the polariton-polariton scattering due to Bose-Einstein statistics does indeed play the major role in the particles piling up in low-energy states, which is the precursor to Bose condensation. Our fits also indicate that at low density, scattering of the polaritons with free electrons plays a more important role than polaritonphonon scattering.