Pseudo-potential investigations of structural, elastic and thermal properties of tungsten disilicide

The plane-wave pseudopotential method using the generalized gradientapproximation within the density functional theory is used toinvestigate the structure and bulk modulus of WSi₂. Thequasi-harmonic Debye model, using a set of total energy versus cellvolume obtained with the plane-wave pseudopotential method, isapplied to the study of the elastic properties and vibrationaleffects. We have analysed the bulk modulus of WSi₂ up to1600~K. The major trend shows that the WSi₂ crystal becomesmore compressible when the temperature rises and the increase ofcompressibility leads to the decrease of Debye temperature. Thepredicted temperature and pressure effects on the thermal expansion,heat capacity and Debye temperatures are determined from thenon-equilibrium Gibbs functions and compared with the dataavailable.