Ab initio calculations of elastic properties of compressed Pt

Abstract

First-principles calculations of the equation of state and single-crystal elastic constants of platinum have been carried out to 650 GPa using density-functional theory (DFT). The present equation of state deduced at 300 K agrees very well with the earlier computational results. The zero-pressure bulk modulus and its pressure derivative obtained in this study are in better agreement with the measured values than those from the earlier calculations. A comparison of the electronic energies indicates that the face-centered-cubic phase is more stable than the hexagonal-close-packed and body-centered-cubic phases up to at least 650 GPa. The values of the zero-pressure single-crystal elastic constants are also close to the experimental values. We also present the high-pressure electronic and vibrational densities of states, as well as the thermal contributions to the free energy.