The diffusion of Ni2+ adatoms on the (001) surface was studied by using molecular dynamics simulations which were based upon a rigid-ion potential model. A wide homologous temperature region, of 0.29 to 0.85, was covered. Two possible adatom positions were found on the surface, in accord with static calculations. From a detailed analysis of the ionic trajectories, it was deduced that the adatom diffused on the surface via hopping and exchange mechanisms. Both processes exhibited an Arrhenius behavior. Two distinct temperature regions were also found which reflected differing energetic requirements for hopping diffusion. This was attributed to the spontaneous creation of anionic adatoms that combined with cationic adatoms at high temperatures. Although the frequency rates for hopping and exchange were comparable, exchange contributed more to diffusion, by as much as an order of magnitude at high temperatures, than did hopping.

Cation Adatom Diffusion on the NiO(001) Surface by Molecular Dynamics Simulation. T.E.Karakasidis, D.G.Papageorgiou, G.A.Evangelakis: Surface Science, 2001, 486[1-2], 46-54