Molecular dynamics simulations of low energy ion sputtering of copper nano-dimensional clusters on graphite substrates

Molecular dynamics simulations have been performed of sputtering of copper clusters, which consisted of 13, 39, 75 and 195 Cu atoms, on a (0 0 0 1) graphite surface by 200 eV Ar ions. The role of multiple Ar-Cu and Ar-C interactions in the polar distributions of backscattered Ar ions was investigated. Yields, energy and angular distributions of sputtered cluster atoms were examined. The azimuthal angular distribution of sputtered Cu atoms exhibit periodic maxima every 60°. The polar angular distributions of sputtered Cu atoms have maxima in directions parallel to the substrate surface for all clusters. The obtained sputtering yields are for a surface with a single Cu cluster deposited. A solution to the problem of comparing the sputtering yield for such a single surface cluster with the yield from a surface with a given cluster coverage is presented.