Molecular-dynamics study of self-diffusion: Iridium dimers on iridium surfaces.

Abstract

Using a molecular-dynamics simulation, we have investigated the mechanisms of single dimer self-diffusion on the (111), (001), and (110) surfaces of fcc iridium. We use a realistic many-body potential, namely, the Rosato-Guillope-Legrand model potential, which involves empirical fittings of bulk properties of the solid. On the (001) and (110) surfaces, evidence of atomic diffusion by exchange mechanisms of the dimer atoms with substrate atoms are found. This is in good agreement with field-ion microscope observations. In addition, a preliminary investigation of the mechanisms of self-diffusion of iridium trimer on the (110) plane has also been carried out.