Surface modification by 1 keV ion impact: molecular dynamics study of an Ar+-Ni(100) collision system

Abstract

An Ar+-Ni(1 0 0) collision system at 1 keV impact energy was investigated by using realistic isoenergetic molecular dynamics (MD) simulations. The sputtering process upon Ar+ ion impact and damage to the Ni(1 0 0) surface are examined in detail. Studying of high bombarding energy regions leads to the necessity of larger and thick enough slabs, otherwise incoming ions can easily pass through the slab; as a result, investigated physical properties may not be revealed. In addition the simulation time should be long enough to observe and to calculate a reliable macroscopic property such as sputtering yield that is addressed in this study. In order to preserve the total energy in the simulation at this collision energy a small time-step (0.1 fs) is used. We have made use of our developed linear scaling parallel MD program to overcome these demands. The Ni(1 0 0) slab is formed by 63700 atoms (122 angstrom x 122 angstrom x 44 angstrom) and the total observation time for each collision event is about 2.25 ps. Several properties such as penetration depths, angular and energy distributions of the reflected Ar and sputtered Ni atoms as well as dissociation time, embedded, scattering, sputtering patterns and geometries of the sputtered clusters are also reported, and the calculated sputtering yield is found to be in good agreement with the available experimental results.