Sputtering of Au by cluster impact

Abstract

Using molecular-dynamics simulation, we study the sputtering of a Au (1 1 1) surface by Au n clusters ( n = 1–201) with impact energies between 0.16 and 64 keV/atom. We vary systematically both the total energy E and the cluster size n, such that the dependence of the sputter yield on these quantities can be discussed. As our basic result, we find the sputter yield Y to scale with the total energy E of the projectile. The sputter yield exhibits a polynomial increase, ∝ E 1.6, up to a critical energy E c ≅ 40 keV, which coincides roughly with the threshold energy for subcascade formation. Above E c, the yield increases approximately linearly with E. These findings are discussed in the light of the considerable data base of Au sputtering which has been built up in recent years due both to experimental and simulational work.