Spin transport of indirect excitons in GaAs coupled quantum wells
  Spin transport of indirect excitons in GaAs/AlGaAs coupled quantum wells was observed by measuring the spatially resolved circular polarization of the exciton emission. The exciton spin transport originates from the long spin relaxation time and long lifetime of the indirect excitons. 
J.R. Leonard, Sen Yang, L.V. Butov, and A.C. Gossard