Exciton magnetic polarons in asymmetric diluted magnetic semiconductor quantum wells

Photoluminescence experiments were carried out for a 3.6-nm ${\mathrm{Cd}}_{0.78}{\mathrm{Mg}}_{0.22}\mathrm{Te}-\mathrm{CdTe}-{\mathrm{Cd}}_{0.86}{\mathrm{Mn}}_{0.14}\mathrm{Te}$ asymmetric quantum well and show the occurrence of two lines, both associated with excitons confined in the quantum-well region. The magnetic-field dependence of the transition energy revealed the formation of magnetic polarons associated only with the excitonic line at the lower energy. Calculations are presented that are consistent with the experimental observations and in particular show that the lower energy line has a component associated with alloy fluctuations at the well-barrier interface in addition to a component associated with polaron bifurcation.