Theoretical study of second and third order elastic constants of β-SiC

First principles calculations of the second and third order elastic constants of the cubic silicon carbide β-SiC have been accomplished using the density functional theory within the local density approximationand the pseudopotential plane-wave method with the Hartwigsen Goedecker Hutter scheme. The secondorder elastic constants Cij compared fairly well with those previously measured by one of us using theBrillouin light scattering technique (P. Djemia) [1]. The ab-initio calculations include parameterspressure dependence determinations in relation with the structural transformation from a zinc Blende toa rocksalt structure. The transition pressure at which arises elastic instabilities is found to be Pt = 113GPa. Also, we investigate the effects of anharmonicity by calculating the third order elastic constantsC_ijk . The experimental values are still unknown and comparisons with our calculations are suitable in thefuture.