Spin Texture in a Cold Exciton Gas

TL;DR

This paper reports the observation of complex spin textures in a cold exciton gas within a GaAs/AlGaAs quantum well, revealing spin transport phenomena and coherence properties around exciton rings.

Contribution

It presents the first detailed observation of spin textures and polarization patterns in a cold exciton gas, highlighting spin transport and coherence in this system.

Findings

Ring of linear polarization observed around exciton rings

Vortex of linear polarization with perpendicular orientation

Extended exciton coherence in polarization vortex region

Abstract

We report on the observation of a spin texture in a cold exciton gas in a GaAs/AlGaAs coupled quantum well structure. The spin texture is observed around the exciton rings. The observed phenomena include: a ring of linear polarization, a vortex of linear polarization with polarization perpendicular to the radial direction, an anisotropy in the exciton flux, a skew of the exciton fluxes in orthogonal circular polarizations and a corresponding four-leaf pattern of circular polarization, a periodic spin texture, and extended exciton coherence in the region of the polarization vortex. The data indicate a transport regime where the spin polarization is locked to the direction of particle propagation and scattering is suppressed.