Ion beam induced coherent displacement in Al on Au system

Molecular dynamics simulations of ion bombardment of heavy metals revealed a few years ago a surprising new damage formation mechanism, the coherent displacement of atoms towards surfaces [Nature 398 (1999) 49]. In principle this mechanism could be used to produce large ordered adatom islands on surfaces with low-fluence irradiation. In practice, however, under the irradiation conditions studied so far most of the surface damage was still produced by chaotic mechanisms, leading to disordered adatom formations. In this paper we examine whether a suitable kind of irradiation of an Al/Au multilayer system would produce surface damage mostly by coherent displacement. We achieve an increase of the coherent displacement probability from the previous 10-30%, giving encouragement for further attempts at optimizing the irradiation conditions