MOLECULAR-DYNAMICS SIMULATIONS OF LOW-ENERGY COPPER ATOM INTERACTION WITH COPPER SURFACES

The interaction between low-energy copper atoms and an atomically smooth [100] copper surface is investigated using a molecular-dynamiCS (MD) computational method. A newly formulated interatomic potential, which empirically combines the Ziegler universal potential at high energy and the embedded-atom many-body potential at low energies, is utilized in the study of near-surface cascade dynamics. The analysis includes sputtering of surface atoms, and reflection and penetration of incident Cu atoms. It is shown that the sputtering yields of low-energy Cu atoms on a [100] Cu surface are in general agreement with the experiments of Hayward and Wolter and with other MD calculations performed by Shapiro and Tombrello using only pair potentials. However, in contrast with pair-potential-type calculations, and in agreement with experimental observations, our work shows a smooth transition from reflection to adsorption as the incident atom energy is lowered. Detailed mechanisms of sputtering and reflection of atoms with energies in the range 10-1000 eV are given.