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

The interaction between low-energy copper atoms and an atomically smoo th [100] copper surface is investigated using a molecular-dynamiCS (MD ) computational method. A newly formulated interatomic potential, whic h 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 inciden t Cu atoms. It is shown that the sputtering yields of low-energy Cu at oms on a [100] Cu surface are in general agreement with the experiment s of Hayward and Wolter and with other MD calculations performed by Sh apiro and Tombrello using only pair potentials. However, in contrast w ith pair-potential-type calculations, and in agreement with experiment al observations, our work shows a smooth transition from reflection to adsorption as the incident atom energy is lowered. Detailed mechanism s of sputtering and reflection of atoms with energies in the range 10- 1000 eV are given.