First-principles calculations of the structural and elastic properties of OsSi2 at high pressure

We investigated the pressure dependence of the structural and elastic properties of OsSi2 in the range 0-60 GPa using first-principles calculations based on density functional theory. Calculations were performed within the local density approximation as well as the generalized gradient approximation to the exchange correlation potential. The calculated lattice constants and atomic fractional coordinates are in good agreement with previous experimental results. The pressure dependence of nine independent elastic constants, c(11), C-22, C-33, C-44, C-55, C-66, C-12, C-13, and C-23, of orthorhombic OsSi2 has been evaluated. The isotropic bulk modulus, shear modulus, Young's modulus, Poisson's ratio, elastic anisotropy, and Debye temperature of polycrystalline OsSi2 under pressure are also presented. (C) 2011 Elsevier B.V. All rights reserved.