The plane-wave pseudopotential approach to density-functional theory (DFT) in the local-density approximation has been applied to investigate a variety of ground-state properties of the 3C, 2H, and 4H polytypes of silicon carbide. The linear-response theory within DFT has been used to obtain lattice-dynamical properties of cubic SiC such as the phonon-dispersion curves, phonon eigenvectors, elastic and Grüneisen constants, as well as the thermal expansion coefficient and specific heat within the quasiharmonic approximation. Finally, we present some results for phonon-dispersion curves in the hexagonal 2H (wurtzite) and 4H structure. These results are analyzed and discussed in view of further applications to temperature-dependent properties.

• Received 8 August 1994

DOI:https://doi.org/10.1103/PhysRevB.50.17054