Theoretical study of the charge transfer in supported transition metal microclusters

The validity of the local charge neutrality approximation within the tight-binding method has been benchmarked against the global charge neutrality approximation. Calculations have been performed for Fe microclusters supported on the Ni(001) surface using a self-consistent spd tight-binding method parametrised to ab initio tight-binding linear muffin-tin orbital results. In order to enhance the effect of the hybridisation between both elements, we have considered an artificial strong interfacial relaxation of the geometries which were predicted by means of molecular dynamics calculations. Our results confirm the validity of the local charge neutrality approximation when a careful parametrisation is used and appropriate values for the charge in each site are elected.