title: Skyrmion formation and optical spin-Hall effect in an expanding coherent cloud of indirect excitons.
abstract: We provide a theoretical description of the polarization pattern and phase singularities experimentally evidenced recently in a condensate of indirect excitons [H. High et al., Nature 483, 584 (2012)]. We show that the averaging of the electron and hole orbital motion leads to a comparable spin-orbit interaction for both types of carriers. We demonstrate that the interplay between a radial coherent flux of bright indirect excitons and the Dresselhaus spin-orbit interaction results in the formation of spin domains and of topological defects similar to Skyrmions. We reproduce qualitatively all the features of the experimental data and obtain a polarization pattern as in the optical spin-Hall effect despite the different symmetry of the spin-orbit interactions.
authors.affiliation: Institut Pascal, PHOTON-N2, Clermont Université, Blaise Pascal University, CNRS, 24 avenue des Landais, 63177 Aubière Cedex, France.
authors.forename: D V
authors.initials: DV
authors.lastname: Vishnevsky
authors.affiliation: Institut Pascal, PHOTON-N2, Clermont Université, Blaise Pascal University, CNRS, 24 avenue des Landais, 63177 Aubière Cedex, France.
authors.forename: H
authors.initials: H
authors.lastname: Flayac
authors.affiliation: Institut Pascal, PHOTON-N2, Clermont Université, Blaise Pascal University, CNRS, 24 avenue des Landais, 63177 Aubière Cedex, France.
authors.forename: A V
authors.initials: AV
authors.lastname: Nalitov
authors.affiliation: Institut Pascal, PHOTON-N2, Clermont Université, Blaise Pascal University, CNRS, 24 avenue des Landais, 63177 Aubière Cedex, France.
authors.forename: D D
authors.initials: DD
authors.lastname: Solnyshkov
authors.affiliation: Institut Pascal, PHOTON-N2, Clermont Université, Blaise Pascal University, CNRS, 24 avenue des Landais, 63177 Aubière Cedex, France and A. M. Prokhorov General Physics Institute, RAS, Vavilova Street 38, Moscow 119991, Russia.
authors.forename: N A
authors.initials: NA
authors.lastname: Gippius
authors.affiliation: Institut Pascal, PHOTON-N2, Clermont Université, Blaise Pascal University, CNRS, 24 avenue des Landais, 63177 Aubière Cedex, France.
authors.forename: G
authors.initials: G
authors.lastname: Malpuech