Lattice dynamics of GaSb

The lattice dynamics of gallium antimonide has been investigated experimentally using the method of coherent inelastic scattering of thermal neutrons. The frequencies for phonons propagating in the [001], [111], and [110] symmetry directions in an undoped gallium antimonide crystal at 300 K have been determined with an estimated precision of 2%. The sample had a carrier concentration of 4.85 × ${10}^{17}$ holes/${\mathrm{cm}}^3$ (upper limit) at 300 K. Both second-neighbor and first-neighbor shell models (SM) were fitted to the measured phonon dispersion curves. Some systematic trends among the fitted parameters for the first-neighbor SM for the gallium group-V compounds (GaP, GaAs, and GaSb) are discussed. The fitted second-neighbor SM parameters have been used to generate a phonon frequency distribution, which in turn has been used in the calculation of the temperature dependence of the specific heat at constant volume and the Debye $\Theta$.