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Séminaire « Propriétés optiques et électroniques des nanostructures » de l’INSP

Dark condensation of excitons in a trap - Romain Anankine - Mercredi 12 octobre 2016 à 11 h

INSP - 4 place Jussieu - 75252 PARIS Cedex 05 - Barre 22-32 - 4e étage, salle 407

Romain Anankine, doctorant dans l’équipe Nanostructures et systèmes quantiques de l’INSP

Abstract

Bosons can experiment a phase transition from a classical gas to a quantum degenerate one when we cool down the system and/or increase the density of particles. For decades, research on Bose-Einstein condensation not only focused on alkaly atoms but also on bosonic semiconductor quasi-particles : electronic excitations, or excitons, are electron-hole pairs bound by Coulomb attraction. Nevertheless, no unambiguous evidences of condensation were demonstrated because of the four-component spin structure where the ground states are dark states, i.e. not coupled to light. In this seminar, I plan to show you the experimental setup I am using to experimentally demonstrate the dark condensation of excitons. I will describe my thesis’s results on quantum darkening of exciton photoluminescence, the formation of quantised vortices and thresholds for spatial and temporal coherence of a 2D trapped gas of excitons when we sweep the bath temperature.