Pressure dependence of dynamical and dielectric properties of 3C and 4H silicon carbide
Institut für Festkörpertheorie und Theoretische Optik, Max-Wien-Platz 1,
07743 Jena, Germany
Accepted: 5 June 1996
We report a first-principle study on the pressure dependence of dynamical and dielectric properties of cubic 3C and hexagonal 4H polytypes of SiC. Results are discussed for the zone-center phonon modes and the tensors of the Born effective charges and the high-frequency dielectric constants. In the case of the hexagonal 4H structure we predict an increasing anisotropy with pressure and a pressure-induced mixing of infra-red active optic modes. The interpretation of recent experiments for 6H SiC is critically examined.
PACS: 61.50.Ks – Crystallographic aspects of polymorphic and order-disorder transformations / 63.20.Dj – Phonon states and bands, normal modes, and phonon dispersion / 78.30.-j – Infrared and Raman spectra and scattering
© EDP Sciences, 1996