Lattice Dynamics of Cubic SiC

The phonon-dispersion curves in the various symmetry directions for cubic SiC have been obtained using a rigid-ion model consisting of short-range central and noncentral interactions and long-range Coulomb interactions among ions of appropriate effective ionic charge. The calculated dispersion in the [111] direction compares well with a recent experimental determination by Feldman et al., who studied the Raman spectra of the various polytypes of SiC. The phonon density of states and the Debye characteristic temperature of SiC have also been calculated.