Phase diagram of microcavity exciton-polariton condensates

Abstract

PACS 71.10.Li -Excited states and pairing interactions in model systems PACS 71.36.+c -Polaritons and related phenomena PACS 67.85.Hj -Bose-Einstein condensates PACS 42.55.Sa -Microcavity and microdisk lasersAbstract -In this work, we study the exciton-polariton condensate phase transition in a microcavity matter-light system in which electron-hole Coulomb interaction and matter-light coupling effects are treated on an equal footing. In the framework of the unrestricted Hartree-Fock approximation applying the two-dimensional exciton-polariton model we derive the self-consistent equations determining simultaneously the excitonic and the photonic condenstate order parameters. In the thermal equilibrium limit, a Kosterlitz-Thouless type phase transition of the exciton-polariton condensations is found and their phase diagrams are constructed. At a given low temperature and in a weak matter-light coupling regime, one finds excitonic (at large Coulomb interaction) and photonic (at low Coulomb interaction) condensations. Increasing the matter-light coupling, polaritonic condensate grows up at intermediate Coulomb interaction. Lowering the Coulomb interaction or increasing the temperature, the excitonic Mott transition happens, at which the exciton-polariton condensates dissociate to free electron-hole/photon. Depending on temperature and excitation density, the phase transition of the exciton-polariton condensates is also addressed in signatures of photoluminescence mapping to the photonic momentum distribution.