Electronic structure of Pd clusters in the tight-binding approximation: influence of spd-hybridization

Abstract

We show that including spd-hybridization in tight-binding model allows an accurate description of the local electronic density of states of Pd clusters in a large range of size and gives reliable site energies. We put in evidence a narrowing of the band with decreasing coordination number accompanied by a significant variation of the local density of states near the Fermi level according to the type of site (vertex, edge, facets or core). From the energetical point of view, we find that a quasi-linear dependence of the attractive part of the potential as a function of the coordination number is better suited than the usual square root dependence. Moreover, we point out the influence of cluster symmetry by comparing the cuboctahedral structure (fcc type) with the icosahedral one (five-fold symmetry) which is adopted by the small fcc clusters.