Dependence on temperature and energy of the heteroepitaxy of small metallic nanoclusters

Deposition at different energies and temperatures of small metallic nanoclusters on metallic substrates is studied by molecular-dynamics simulations. Small-, Co/Cu(001), and large-misfit, Cu/Au(001) and Au/Cu(001), systems are considered. The rise in temperature improves the epitaxial order, although its effect is smaller in large-misfit systems. Thus, by increasing this parameter, non-epitaxial clusters can turn their structure into epitaxial in the case of Co/Cu(001), into aligned in Cu/Au(001), and into layered in Au/Cu(001). Therefore, the characteristics of the alignment are determined by the properties of the material. In addition, the influence of the initial structure is more marked in Co and Cu clusters, since they can reproduce locally other phases. Epitaxy can also be improved if the deposition energy is increased, although the deposited cluster loses its original shape progressively. Its effect is different depending mainly on the degree of misfit. An increase in energy (of up to 0.75 eV/atom) produces similar effects, but more noticeable, as a rise in temperature.