High pressure study of cubic BN and SIC (Raman scattering and EDS)

Abstract

First-order Raman spectra and lattice parameters of BN and SiC were measured simultaneously up to a pressure of 34 and 45 GPa. The bulk moduli, their pressure derivatives and the volume dependence of Gruneisen parameters of LO and TO phonons were obtained. The average Gruneisen parameter for BN does not change much; on the contrary, the same parameter for SiC decreases under pressure. The definite connection between the crystal stability, the pressure behaviour of the optical phonons and the electron structure of the ionic cores is pointed out.

Key Words:

• EOS
• Raman scattering
• Gruneisen parameter
• BN
• SiC