Temperature dependence of the Gibbs energy of vacancy formation of fcc Ni

Quantum-mechanical calculations are used to determine the temperature dependence of the Gibbs energy of vacancy formation in nickel. Existing data reveal a discrepancy between the high-temperature estimates from experiments and low-temperature approximations from density functional theory. Our finite-temperature calculations---which include the effects of magnetism and fully interacting phonon vibrations---demonstrate that this discrepancy is mostly caused by the previously neglected explicit anharmonic contribution.