FIRST-PRINCIPLES STUDY OF Ni ADSORPTION ON Mo(110)

The adsorption of Ni atom on the Mo(110) surface has been studied within the density functional theory framework. It turned out that Ni-Mo surface alloy was formed with Ni atoms substituting Mo atom in the outermost layer. The subsurface site adsorption was found to be not preferred. Geometric analysis showed that the rumpling between substitutional Ni and Mo in the first alloy layer was about 0.108 angstrom at medium and low coverage (Theta). In addition, the diffusion of Ni on bare and Ni-substitutional Mo(110) surface has been investigated. It was shown that the diffusion energy barrier was reduced as the increase of coverage on bare Mo(110) surface, which supports the switch of growth mode layer-by-layer to Stranski-Krastanov as the function of coverage. Substitutional Ni atom only slightly increases the energy barrier for Ni diffusion on Mo(110) surface.