<i>Ab initio</i>calculation of structural and lattice-dynamical properties of silicon carbide

Abstract

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 Gr\"uneisen 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.