Static and dynamical properties of SiC polytypes

Static and dynamical properties of $3C, 2H, 4H, 6H,$ and $15R$ SiC polytypes have been calculated using a modification of Tersoff 's potential for covalent multicomponent systems. Structures and vibrational frequencies are in good agreement with experimental results. For uniaxial polytypes, the dependence of the optical frequencies on propagation angle has been studied. The relative intensity of Raman bands has been calculated using a bond polarizability model. Isotope shifts, phonon eigenvectors and relative phase for longitudinal and transversal modes of $3C$ SiC for the dispersion branches along the $〈111〉$ direction have been determined and compared with experimental results. The success of this calculation opens up the possibility of calculating static and dynamical properties of disordered Si-C systems.