Photoluminescence spectroscopy on single CdSe quantum dots in a semimagnetic ZnMnSe matrix

Photoluminescence spectroscopy with high spatial resolution has been applied to study single CdSe quantum dots embedded in a semimagnetic ZnMnSe matrix. The exchange interaction between the exciton and Mn2+ ions of the crystal matrix results in the formation of a ferromagnetically aligned spin complex, a quasi-0D excitonic magnetic polaron. We demonstrate, that the energy shift of the EMP with temperature and excitation power, respectively, directly reflects the change of the magnetization, in particular the spin temperature, on a nanometer scale.