First-principles study of the thermal properties of metal Zr

A first-principles study of the thermal properties of hcp metal Zr using the pseudopotential plane-wave method in the framework of the density-functional theory and density-functional perturbation theory is reported. The phonon spectra and static total energies are calculated for Zr with different lattice parameters, and free energies at different temperatures are obtained in the quasiharmonic approximation according to the criterion of free energy minimum. The temperature-dependent coefficients of thermal expansion, bulk modulus and specific heat at constant volume (pressure) are presented. Calculated results for the thermal properties are in good agreement with the available experimental data in a wide range of temperature. The coefficients of thermal expansion obtained from first-principles approach and Debye-Gruneisen model are compared. The electronic contribution to the specific heat is found to be not negligible at high temperature.