Comparison of second-order Raman scattering measurements with a phonon density-of-states calculation in GaSb

Second-order Raman measurements have been made on oriented GaSb with various combinations of incident and scattered polarizations in order to obtain the three irreducible components of the Raman tensor Γ₁, Γ₁₅, and Γ₁₂. The dominant Γ₁ Raman spectrum is compared with the recently reported one-phonon density of states calculation based upon shell-model parameters that were fitted to neutron data. Significant deviations exist and we believe these to be artifacts of the shell-model parameters used. The observed dependence of the 2LO(Γ) and 2TO(Δ) Raman peaks upon incident photon energy was attributed to resonance Raman effect with the E₁+Δ₁ direct gap and with the Γ_15ν→Δ1c indirect gap, respectively.