Equation of State and distribution of density defects for a quasi-condensate of dipolar excitons
Dipolar excitons of GaAs coupled quantum wells provide a model system to study collective phenomena that can emerge in two-dimensional semiconductors. Indeed, these are characterised by a large electric dipole moment and a long radiative lifetime allowing them to thermalise to sub-Kelvin temperatures. A gas of dipolar excitons can then realise a two-dimensional quasi-condensate marked by its macroscopic spatial coherence. At INSP, experiments have been performed, in collaboration with C2N and the University of Grenoble, in order to quantifythermodynamically the quasi-condensation of dipolar excitons, as well as the topology of the phase transition. These works constitute a promising step towards detecting the fingerprints of the Berezinskii-Kosterlitz-Thouless transition in semiconductors.
Defect Proliferation at the Quasicondensate Crossover of Two-Dimensional Dipolar Excitons Trapped in Coupled GaAs Quantum Wells
Suzanne Dang, Romain Anankine, Carmen Gomez, Aristide Lemaître, Markus Holzmann, François Dubin
Phys. Rev. Lett. 122, 117402 – Published 22 March 2019 DOI : 10.1103/PhysRevLett.122.117402