First-principles calculations of the structural and elastic properties of β-FeSi2 at high-pressure

The pressure dependence of the structural and elastic properties of β-FeSi2 in the range 0–60 GPa was investigated 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 internal parameters are in good agreement with previous experimental results. The nine independent elastic constants, c11, c22, c33, c44, c55, c66, c12, c13, and c23, of orthorhombic β-FeSi2 have been evaluated. The isotropic bulk modulus, shear modulus, Young’s modulus, Poisson’s ratio, elastic anisotropy, and Debye temperature of polycrystalline β-FeSi2 under pressure are also presented.