Interatomic potential for platinum and self-diffusion on Pt(111) surface by molecular-dynamics simulation

Abstract

We present a many-body interatomic potential for Pt within the second-moment approximation of the tight-binding model by fitting to the volume dependence of the total energy of the metal, computed by first-principles augmented-plane-wave calculations. This was used, in conjuction with molecular-dynamics simulations, to study the diffusion of Pt adatoms and dimers on Pt(111) surface. The diffusion coefficient of the adatoms and dimers was computed and was found to present Arrhenius behavior. The migration energies and pre-exponential factors for hopping diffusion mechanism were determined as well and compared with experimental data obtained by scanning tunnelling microscopy, field ion microscopy methods and previous calculations. Both quantities were found to be in good agreement with measurements. At high temperatures we have also investigated a concerted exchange adatom diffusion mechanism, where there is a participation of two surface atoms belonging to nearest-neighbour rows. © 2009 Springer Science + Business Media B.V.