First-principles study of initial stage of Ni thin-film growth on a TiO₂ (110) surface

The bonding structure and binding character for the initial stage of thin-film growth of Ni on a rutile (110) surface were studied using first-principles density functional theory. Our results show that, in the first monolayer, Ni atoms are preferentially adsorbed on top of bridging oxygen atoms and upon secondary surface oxygen. The bond strength between Ni adatom and substrate is much stronger than that between Ni adatoms. About 0.3 electrons are transferred from Ni atoms to substrate in low coverage; the adsorption of additional Ni atoms on neighboring sites decreases this transfer. In addition to the ionic bonding component, some covalent character is found in the Ni adatom–substrate bond.