The elastic properties of hexagonal osmium under pressure: The first-principles investigations

The first-principles methods are adopted to investigate the equation of state (EOS) and elastic constants of hexagonal osmium at applied pressures up to 100 GPa. The obtained normalized volume dependence of the applied pressure is in agreement with the experiment. Five independent elastic constants at zero pressure and high pressure are calculated. From the obtained elastic constants, mechanical anisotropy, acoustic velocity anisotropy and Debye temperature ΘD at the applied pressure are also calculated. The results obtained are consistent with the available experimental and theoretical data. The acoustic velocity anisotropy as a function of the applied pressure is presented.