Resonant Raman scattering by longitudinal optical phonons in Cd0.55Mn0.45Te at the E0gap

The authors report on resonant Raman scattering by longitudinal optical (LO) phonons near the E 0 gap in Cd 0.55 Mn 0.45 Te at T=300 K. Absolute values for the Raman efficiencies are determined for allowed one-LO-phonon and forbidden one- and two-LO-phonon scattering. The maxima of the Raman efficiencies occur for both configurations whenever the energy of the scattered photon equals the gap energy E 0 . A comparison with theoretical calculations, assuming uncorrelated electron-hole pairs as intermediate states, shows that the forbidden one-LO-phonon scattering is dominated by the impurity-induced Frohlich interaction. From the two-LO-phonon resonance curves, they obtain a gap energy E 0 of 2.04 eV and a gap energy broadening eta of 25 meV.