First-principles calculations of the vacancy formation energy in nickel

Abstract

Within the framework of density functional theory, we investigate with the VASP code three key properties of a vacancy in crystalline nickel: the formation, migration and activation energy. We use Blochl's all-electron-like projector augmented wave method (PAW) to perform self-consistent total-energy structure calculations in the supercell approximation and pseudopotentials to describe the computationally expensive core-valence interaction. All calculations have been carried out using either the local spin density approximation (LSDA) or the generalized gradient approximations (GGA). In a first step we show that the inclusion of non local effects improves significantly the détermination of various well known experimental properties of the bulk (lattice parameter, magnetic moment, bulk modulus, cohesion energy ...). Thus, we conclude that the non local approach leads to a better estimation of vacancy formation (1.4 eV), migration (1.28 eV) and activation (2.65 eV) énergies at 0 K.