Polariton dynamics and Bose-Einstein condensation in semiconductor microcavities

TL;DR

This paper presents a theoretical model of polariton dynamics in semiconductor microcavities, showing how exciton-polariton scattering leads to Bose-Einstein condensation at densities below saturation, aligning with experimental observations.

Contribution

It introduces a new theoretical framework for understanding polariton relaxation and predicts BEC at lower densities than previously thought.

Findings

Maximum polariton distribution shifts with pump-power and temperature.

Macroscopic occupancy achieved at high pump-power.

Predicted BEC driven by exciton-polariton interactions below saturation density.

Abstract

We present a theoretical model that allows us to describe the polariton dynamics in a semiconductor microcavity at large densities, for the case of non-resonant excitation. Exciton-polariton scattering from a thermalized exciton reservoir is identified as the main mechanism for relaxation into the lower polariton states. A maximum in the polariton distribution that shifts towards lower energies with increasing pump-power or temperature is shown, in agreement with recent experiments. Above a critical pump-power, macroscopic occupancies (5 \times 10^4) can be achieved in the lowest energy polariton state. Our model predicts the possibility of Bose-Einstein Condensation of polaritons, driven by exciton-polariton interaction, at densities well below the saturation density for CdTe microcavities.