Electronic structure, elasticity, Debye temperature and anisotropy of cubic WO 3 from first-principles calculation.

The electron structure, elastic constant, Debye temperature and anisotropy of elastic wave velocity for cubic WO3 are studied using CASTEP based on density functional theory. The optimized structure is consistent with previous work and the band gap is obtained by computing the electronic structure; the top of the valence band is not at the same point as the bottom of the conduction band, which is an indirect band-gap oxide. Electronic properties are studied from the calculation of band structure, densities of states and charge densities. The bulk and shear moduli, Young's modulus, hardness and Poisson's ratio for WO3 are studied by the elastic constants. We calculated acoustic wave velocities in different directions and estimated the Debye temperature from the acoustic velocity. The anisotropy of WO3 was analysed from the point of view of a pure wave and quasi wave.