WEAK-LOCALIZATION EFFECTS ON SPIN RELAXATION OF EXCITONS IN QUANTUM-WELLS

We have analyzed the effect of weak disorder, originated from impuriti es and imperfections that scatter excitons elastically, on spin-relaxa tion dynamics of excitons in a quantum well, assuming dominating excha nge-induced transition between two optically active excitonic states w ith spin +1 and -1. The quantum interference effects give rise to the characteristic quantum localization corrections to both longitudinal a nd transverse spin-relaxation rate. These corrections are time depende nt and can change sign during a time interval of observation. Similar corrections are also expected for the spin-relaxation rate of electron s in the spin splitted conduction band of zinc-blende semiconductors.