Interface exciton magnetic polaron in ZnSe/Zn1−xMnxSe quantum-well structures

A study of cw photoluminescence and photoluminescence excitation spectra of ZnSe/${\mathrm{Zn}}_{1\mathrm{-}\mathit{x}}$ ${\mathrm{Mn}}_{\mathit{x}}$Se quantum wells with semimagnetic barriers in a magnetic field clarifies the scenario of magnetic polaron formation for the situation when the light-hole exciton is the electronic ground state at zero magnetic field. It is shown that magnetic polarons are formed by heavy-hole excitons when they become the lowest exciton state at a certain magnetic field due to the giant Zeeman splitting. The magnetic polaron is concluded to be localized at the interface which is favored by a magnetic-field-induced type-I–type-II transition for heavy holes.