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Séminaire des doctorants de l’INSP

Condensation des excitons indirects dans des doubles puits quantiques de GaAs - Suzanne Dang - Mercredi 2 mai 2018 à 16 h

INSP - Sorbonne Université - 4 place Jussieu - 75005 Paris - Barre 22-32, 2e étage, salle 201

Suzanne Dang, doctorante dans l’équipe Photons - Magnons et Technologies Quantiques (PMTeQ) de l’INSP.

Abstract

Indirect excitons confined in GaAs double quantum wells (DQW) constitute a model system to investigate quantum phases transition. Indirect excitons result from the Coulomb attraction between spatially separated electrons and holes, a situation which is directly achieved by applying an electric field perpendicular to the plane of a DQW. In recent experiments we have reported signatures of quantum coherence and quantized vortices in the photoluminescence radiated by indirect excitons confined in a two-dimensional trap [1]. Here we show that in this geometry the excitons quantum phase transition obeys the Berezinskii-Kosterlitz-Thouless (BKT) mechanism, as expected theoretically.

In this seminar, I will first present the composite boson we are studying : indirect excitons in double quantum wells and the possible quantum phase transitions that we are expected to observe at low temperature ( 1K). Finally, I will present you our recent results that shows strong evidences for the topological BKT phase transition.

[1] R. Anankine et al. , Phys. Rev. Lett. , 2017, 118, 127402.