Behavior of Cu and Ni clusters landing at grazing incidence on Ni(0 0 1) and Cu(0 0 1) surfaces: Molecular dynamics simulation

Abstract

The interaction between a metal cluster and an fcc metal substrate surface is investigated for a grazing incidence by way of molecular dynamics (MD) simulations combined with a Tight-Binding potential (TB). The simulation of heterogeneous deposits, viz., Cu66→Ni(001) and Ni66→Cu(001), as well as homogeneous deposits, viz., Cu66→Cu(001) and Ni66→Ni(001), are achieved with incident energies around the cluster cohesive energy, namely, 1, 3.49, 4 and 5eV/at, for Cu cluster and 3, 4.44, 5 and 6eV/at, for Ni cluster. The deposit dependence upon the cluster characteristics along with the substrate parameters is analyzed. The results indicate no significant effect of the material of the cluster on the microstructure and the morphology of the latter in the case of homogenous deposition, whereas the migration is seen to be more sensitive to the cluster kinetic energy as well as the cohesive energy of the substrate. On the contrary, in the case of a heterogeneous deposition the migration is slightly dependent upon the cohesive energies of the cluster and the substrate. The microstructure and the morphology are better established for Cu clusters than for Ni clusters, for the compressibility of the nickel substrate is lower than that of copper. Besides, novel heartbeat-type instability is reported that corresponds to an oscillatory behavior of the elongation parameter while the cluster is spreading on the substrate.