Photoexcited spin states in diluted magnetic semiconductor quantum structures

Exciton photoluminescence in a diluted magnetic asymmetric quantum well has given clear evidence of "asymmetric exciton magnetic polaron states" in ma gnetic fields. The theoretical calculation to interpret the observed magnet o-optical data has clarified the importance of exciton localization associa ted with the interface disorder and the alloy potential fluctuation in addi tion to the exciton magnetic polaron formation in the asymmetric diluted ma gnetic barrier. The possibility of a "bifurcated" exciton states is discuss ed. The transient four-wave-mixing nonlinear spin selective optical measure ments revealed the spin-structure of excitons and biexcitons in diluted mag netic quantum structures. The effects of the magnetic field on biexciton st ates have been investigated. The photoluminescence transition from the biex citon to exciton states has been investigated in magnetic fields, and the s tability of the biexciton states in either bonding (spin singlet) or anti-b onding states (spin triplet) is discussed. We have proposed methods to dedu ce the interface magnetism in the diluted magnetic quantum structures from the high-field Zeeman splitting of exciton photoluminescence up to 60 T. (C ) 2001 Elsevier Science B.V. All rights reserved.