Structural, mechanical and electronic properties and hardness of ionic vanadium dihydrides under pressure from first-principles computations.

ABSTRACT: Based on a combination of the CALYPSO method for crystal structure prediction and first-principles calculations, we explore the crystal structures of VH₂ under the pressure range of 0-300 GPa. The cubic Fm-3m phase with regular VH₈ cubes is predicted to transform into orthorhombic Pnma structure with fascinating distorted VH₉ tetrakaidecahedrons at 47.36 GPa. Both the Fm-3m phase at 0 GPa and the Pnma phase at 100 GPa are mechanically and dynamically stable, as verified with the calculations of elastic constants and phonon dispersions, respectively. Moreover, the calculated electronic band structure and density of states indicate both stable phases are metallic. Remarkably, the analyses of the Poisson's ratio, electron localization function (ELF) and Bader

SUBMITTER: Wang W 

PROVIDER: S-EPMC7264295 | biostudies-literature | 2020 Jun

REPOSITORIES: biostudies-literature