A comparative study of surface phonons on CdTe(1 1 0) and InSb(1 1 0)

We have studied the lattice dynamics of the CdTe(1 1 0) and InSb(1 1 0) surfaces by using the adiabatic bond-charge model. The atomic geometry and electronic informations for the phonon calculations have been obtained by using the local density approximation of the density functional theory and ab initio pseudopotentials. The calculated phonon dispersion curves for InSb(1 1 0) are in agreement with the results obtained in a recent helium atom scattering experiment. The surface phonon modes on the InSb(1 1 0) and CdTe(1 1 0) surfaces exhibit nearly similar displacement patterns. This is mainly due to the fact that both bulk materials have nearly identical lattice constants, as well as a similar cation and anion mass difference. It is pointed out that, due to the larger ionicity of CdTe, the surface phonon energies are generally lower for CdTe(1 1 0) than for InSb(1 1 0).