Investigations on the structural, electronic, elastic and thermodynamic properties of niobium silicide under high temperature and pressure

A first principles investigation on the structural, electronic and elastic properties of NbSi2 has been calculated using the plane wave pseudo-potential density functional theory (DFT) method. The lattice constants and elastic constants are obtained. The characters of the band structure and the density of states of niobium silicide (NbSi2) are analyzed, which shows that NbSi2 is metallic. The bulk, shear and Young’s modulus for NbSi2 are also calculated. The Debye temperature is calculated from the average elastic wave velocity obtained from the shear and bulk modulus. The thermodynamic properties including the heat capacity CV and CP, thermal expansionαα, entropy S   and Grüneisen parameterγγhave been calculated at temperatures from 0 to 2100 K and pressures from 0 to 30 GPa using the quasi-harmonic Debye model. We also found that the present work can give a reference to those not to be experimentally investigated.