Exciton enhancement of spin relaxation in diluted magnetic semiconductor quantum wells

The authors performed pump-probe magneto-optical Kerr spectroscopy to explore the role of excitonic effects on the electron and hole spin relaxation in Cd1-xMnxTe-based quantum well structures. Particularly, important information was obtained from detailed interpretation of the temp. and wavelength dependence of the obsd. transient magneto-optics in specially engineered structures. In Mn-rich wells the electron spin relaxation is strongly enhanced in the exciton due to the increased mass of the bound electron-hole pair, in agreement with earlier predictions. An even stronger enhancement of the relaxation time is found for the hole spin, which is explained by the addnl. mixing of heavy-hole and light-hole states in the bound state. In structures where Mn is confined to the barrier region, a different behavior is obsd., indicative for a competition of various contributions. [on SciFinder (R)]