Luminescence spectra produced by exciton relaxation at local magnetizationfluctuations in semimagnetic semiconductors

An analysis is made of the exciton angular- momentum alignment along a fluc tuation in local magnetization, which is the first stage in evolution of th e localized-exciton spin state in a semimagnetic semiconductor. It is shown that spin relaxation of localized excitons subjected to resonant optical e xcitation is accompanied by their relaxation in energy. When excited by pol arized light, this process gives rise to an anisotropic angular- momentum d istribution in the spectrum of final exciton states and, hence, to polariza tion of the secondary luminescence. Luminescence spectra of a cubic crystal are calculated, and the possibility of their experimental observation disc ussed. (C) 1998 American Institute of Physics. [S1063-7834(98)00312-8].