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

Abstract

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 ${\Gamma }_1$, ${\Gamma }_{15}$, and ${\Gamma }_{12}$. The dominant ${\Gamma }_1$ 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 $2\mathrm{LO}\left(\Gamma \right)$ and $2\mathrm{TO}\left(\Delta \right)$ Raman peaks upon incident photon energy was attributed to resonance Raman effect with the $E_1+{\Delta }_1$ direct gap and with the ${\Gamma }_{15\nu }\to {\Delta }_{1c}$ indirect gap, respectively.