The axial compressibility, thermal expansion and elastic anisotropy of Hf 2SC under pressure

Using plane-wave pseudopotential density functional theory and Debye model, we have studied the axial compressibility, thermal expansion and elastic anisotropy of Hf2SC at different temperature and pressure. It is found that the bulk moduli Ba and Bc (along the a and c axes, respectively) almost linearly increase with pressure and the former is always smaller than the latter. The ratio of Bc/Ba has a trend of gradual increase as the pressure increases. We observe that the Grüneisen parameter γ and thermal expansion coefficient α decrease when increasing pressure, on the contrary, the anisotropy, Debye temperature, longitudinal wave velocity and transverse wave velocity increase with pressure