Excitons as intermediate states in spin-flip Raman scattering of electrons bound to donors inCd1−xMnxTe epilayers

The resonance behavior of the spin-flip Raman scattering in semimagnetic ${\mathrm{Cd}}_{1\mathrm{-}\mathit{x}}$ ${\mathrm{Mn}}_{\mathit{x}}$Te epilayers has been used to investigate the scattering process itself as well as to identify the state of the carrier that changes its spin. The characteristic variation of the Stokes shift with magnetic field, a magnetic polaron effect for vanishing magnetic field, and the independence of the scattering efficiency of laser power indicate that a donor-bound electron changes its spin orientation. According to magnetic dipole selection rules for the spin-flip scattering of electrons, the Raman signal shows resonances with excitonic transitions involving the ${\mathit{m}}_{\mathit{j}}$=±1/2 hole states as they can be characterized by luminescence and photoluminescence excitation spectroscopy. The pronounced resonance behavior allows a very accurate comparison of the resonance energy of the spin-flip Raman scattering with the energetic position of the corresponding free exciton peak in the photoluminescence excitation spectrum. We therefrom conclude that a donor-bound exciton plays the role of the intermediate state in this scattering process.