Effect of alloy potential fluctuations on the exciton magnetic polaron in the bulk diluted magnetic semiconductors Cd1-xMnxTe -: art. no. 193202

A theory for exciton magnetic polarons (EXMP's) in diluted magnetic semiconductors localized by the sp-d exchange interaction with assist of alloy potential fluctuations (APF's) is presented within the molecular-field approximation. First, we show that the self-trapped EXMP in Cd1-xMnxTe is rarely realized except at quite low temperatures below similar to1 K. Then, we incorporate the effect of APF's with the optimal fluctuation method; the calculated results turn out to be consistent with the photoluminescence data above 1 K observed after band-edge excitation. This strongly suggests the necessity of APF's to localization of EXMP's. The calculation with APF's further demonstrates that the luminescence due to the EXMP in Cd1-xMnxTe is observed clearly from xsimilar to0.05, which is also consistent with the experiment.