Molecular dynamics of place exchange of metal adatoms with fcc (100) surfaces during deposition

We report results of molecular-dynamics simulations of metal-deposition-induced exchange on fee (100) metal surfaces. In these simulations, the adsorption energy facilitates nonthermal ''transient exchange'' between an adatom and a substrate atom by significantly heating a local surface zone around the impact site. Detailed analysis of the dynamics of the deposition-induced exchange mechanism reveals an unexpected momentum effect, which influences the degree of transient exchange. When adatoms are heavier than the substrate atoms, exploitation of the temporarily hot deposition zone is maximized. In contrast, adatoms that are lighter than the substrate recoil from the surface upon impact, allowing the local impact zone to cool before the adatom has a second chance at exchange. Thus transient exchange is somewhat inhibited.