Spatial and energy distributions of particles sputtered from NiPd single crystals

Molecular dynamic simulation has been used to study the sputtering of NiPd single-crystal disordered compounds. Spatial distributions, as well as the energy of Ni and Pd particles sputtered from the NiPd (001) face have been investigated, for Ar bombarding ions of energies E0 ranging from 0.1 keV to 5 keV, incident at different angles. The results have shown a predominant exit both of Ni and Pd atoms near the same close-packed directions, in contrast to what is observed for ordered binary compounds. For unchanged composition of the surface, the emission of Ni in the <011> close-packed directions is significantly greater than the emission of Pd. When the composition of top layers was changed, however, the opposite is observed and the exit of Pd prevails. Energy dependence and energy spectra of sputtered components have been analysed as well as the origin and the number of the generation of ejected particles. The observed trends are explained by the particular behaviour of correlated collisions in single crystals.