Static investigation of the small clusters on the Cu(111) and Au (111) surfaces

The diffusion properties of small clusters Agn, Cun, and Aun on the Cu(111) and Au(111) surfaces were studied using the molecular statics (MS) in order to understand the atomistic processes underlying the motion. In this work, the atomic interaction potential is modeled by a semi empirical Embedded Atom Method (EAM), while the drag method is used to determine the static activation energy for each diffusion path. The presented results indicate that the dimer can diffuse on the (111) surface via the zig-zag and concerted motion mechanisms. The trimer diffuses according to the concerted motion mechanism. For the tetramer diffusion, the mechanism that consumes the least amount of energy is the zig-zag motion, in which only two atoms are needed for the diffusion process at one time. This allows finding a static activation energy smaller compared to the trimer diffusion.