Model study of keV-ion mixing of metallic interfaces: Influence of materials properties and deposited energy.

Abstract

Using molecular-dynamics simulation, we study the mixing induced by keV ions in metals and metallic bilayers and its dependence on materials properties. This is possible since we use many-body potentials of the tight-binding form, in which the cohesive energy and the heat of mixing can be independently assigned. In the simulations, the interface mixing shows an inverse-square dependence on the cohesive energy, and a stronger than linear dependence on the heat of mixing. Both features are in accordance with the experimental observations, and with existing phenomenological models. Mixing depends quadratically on the deposited energy. These features are in even quantitative agreement with a phenomenological model of thermal spike mixing. Only small mass effects in the mixing of isotopic systems are observed.