Magnetic field and temperature tuning of resonant Raman scattering in diluted magnetic semiconductors

Abstract

We report the observation of the resonance enhancement of the Raman line in ${\mathrm{Cd}}_{1\mathrm{\ensuremath{-}}\mathrm{x}}$${\mathrm{Mn}}_{\mathrm{x}}$Te associated with the LO phonons in combination with the spin flip of ${\mathrm{Mn}}^{2+}$. The resonance condition is fulfilled when the large magnetic-field-induced exciton splitting allows one of its components to be brought into coincidence with the Raman line. The exciton splittings are due to the large effective g factors of the conduction and valence bands arising from the strong ${\mathrm{Mn}}^{2+}$--band-electron exchange interaction. The associated temperature tuning is also observed at a constant magnetic field. The feasibility of magnetic field tuning of resonance conditions for Raman scattering in diluted magnetic semiconductors is a result of the sensitive manner in which excitonic splittings depend on magnetic field, temperature, and concentration of magnetic ions. In addition, new higher order spin-flip Raman scattering is observed; an interpretation for their occurrence is presented.