Thermodynamic properties and lattice dynamics of silver at high pressure: a first-principles study

The pressure dependence of the thermodynamic properties of silver is calculated in the quasiharmonic approximation using the ab initio pseudopotential plane-wave method and the density-functional perturbation theory. At a given temperature and pressure, the thermodynamic equilibrium volume of the crystal is obtained from the first-principles P-V-T equation of state which is constructed from the Helmholtz free energy. The calculated thermal quantities such as the equilibrium volume, thermal expansion coefficient, bulk modulus, and heat capacity are in good agreement with available experimental data in a wide range of temperatures and pressures. We also present the phonon dispersion and the phonon density of states under different pressures.