The collective diffusion in chain structures on anisotropic substrates like (112) body-centered cubic and (110) face-centered cubic surfaces, with deep troughs in the substrate potential, was studied. The chain structures were aligned normal to the troughs, and could move only along the troughs. Mass transport in such anisotropic systems was studied by combining theoretical arguments with numerical simulations. It was found that a mechanism similar to soliton diffusion, rather than single particle diffusion, remained effective at temperatures well above the melting point of the ordered chain structures. This mechanism was directly related with an ordered phases that appeared at much lower temperatures. As a result, the influence of frozen disorder was also still visible above the melting point. A strong dependence of the pre-exponential factor, and a weak dependence of the activation energy upon the concentration of frozen surface defects, was predicted; and confirmed by simulation.

Diffusion in a Strongly Correlated Anisotropic Overlayer. I.F.Lyuksyutov, H.U.Everts, H.Pfnür: Surface Science, 2001, 481[1-3], 124-34