Authors: Matti Hellström, Daniel Spångberg, Kersti Hermansson and Peter Broqvist
Using hybrid density functional theory, we investigate structural and electronic properties of small Cun clusters (with n ≤ 9) adsorbed on the nonpolar ZnO(101̅0) surface. The Cu clusters grow in a planar fashion up to a size of six atoms, after which the clusters take on a polyhedral shape. We find even–odd alternations with respect to both cluster stability (for n = 1–6) and cluster charge, as a function of the number of atoms. Even-numbered clusters are always charge-neutral, while odd-numbered clusters can become positively charged by donation of an electron to the ZnO conduction band, which can be traced back to the fact that the ionization energies of odd-numbered gas-phase Cu clusters are lower than for even-numbered ones. The most stable adsorbed odd-numbered clusters are neutral and planar forn ≤ 3 and positively charged and polyhedral for n ≥ 7. For n = 5, both neutral planar and positively charged polyhedral configurations are similarly stable.
J. Phys. Chem. C, 2014, 118 (12), pp 6480–6490