MD simulation of atomic displacements in metals and metallic bilayers under low energy ion bombardment at 300 K

MD simulations of 100 eV Ar ion bombardment of (1 0 0) Ni and Al as well as Al/Ni bilayer crystals at 300 K have been performed and compared to previo us calculations at 0 K. The Al/Ni bilayer crystal consisted of one Al layer on a (1 0 0) Ni substrate. Sputtering yields for Ni and Al/Ni show no temp erature dependence, while for Al a pronounced increase with temperature was observed. The contributions of different mechanisms to the production of s urface and bulk defects are discussed. The mean square displacement (MSD) o f atoms is in all cases larger at 300 K as compared to 0 K. The larger MSD at 300 K is mainly due to an increase in lateral (perpendicular to the ion beam) motion of displaced atoms. Similar the number of atomic jumps, in whi ch an atom leaves its original Wigner-Seitz cell, increases in all cases wi th temperature. For the pure elements the production of bulk vacancies and interstitials decreases with temperature, but the number of surface vacanci es and ad-atoms increases with temperature. For the bilayer system practica lly no temperature dependence for defects was observed. (C) 1999 Elsevier S cience B.V. All rights reserved.