First-principles study of structural, electronic and elastic properties of diboride of vanadium

We have performed first-principles study on the bonding nature, elastic property and hardness of vanadium diboride (VB2). The nature of chemical bonding can be recognized as a combination of covalent, ionic and metallic bonds from their electronic structures. Density of state, valence charge density and Mulliken population have also been explored to assess the origins of “pseudogap” and charge transfer. The five independent elastic constants were derived and the bulk modulus, Young's modulus, shear modulus and Poisson's ratio were determined. The calculated anisotropy factors indicate that VB2 are largely compression and shear isotropic. While the behavior under high pressure shows the anisotropy is weak. The model for hardness calculation uses Mulliken population. This is a quantitative theoretical prediction of the elastic properties and hardness of VB2 and it still awaits experimental confirmation.