Structure and thermodynamic properties of ZrH2

The structural and elastic properties of ZrH2 are investigated using the full-potential linearized augmented plane wave plus local orbital method within the generalized gradient in the frame of the density functional theory. The ground state properties such as lattice constant, bulk modulus and elastic constants are in good agreement with numerous experimental and theoretical data. Through the quasi-harmonic Debye model, in which the phononic effects are considered, the thermodynamic properties have been obtained successfully, such as thermal expansion coefficient, Debye temperature and heat capacity in the whole pressure range from 0 to 50 GPa and temperature range from 0 to 1300 K. The results show that heat capacity increases with temperature, tending to the Dulong-Petit limit. Debye temperature increases with pressure, however, decreases with temperature. For a given pressure, thermal expansion coefficient increases with temperature, while the increase gradually slows down. (authors)