Adsorption and surface diffusion of au monomers and dimers on strongly correlated nio(001) surfaces

The adsorption and diffusion of Au monomers and dimers on strongly correlated antiferromagnetic NiO(001) were examined by density functional theory combined with the on-site Coulomb repulsion U. The preferential adsorption sites for the monomers and dimers were found to be near the surface O atoms. For surface diffusion of the Au monomer, the spin-dependent, anisotropic, and very fast diffusion was observed. In the case of dimer diffusion, isotropic hopping diffusion was observed as the lowest-energy diffusion mechanism, and the diffusion barrier was lower than the diffusion barrier of the Au dimer on MgO(001). This suggests that the Au dimer, the stable and smallest cluster, diffuses more easily on NiO(001) rather than on MgO(001). These findings provide important information for the sintering of Au clusters on NiO(001), which is essential for optimizing a catalytic process.