Surface diffusion and growth of patterned nanostructures on strained surfaces

We propose a method of controllable growth of patterned nanostructures on a surface with a self-organized network of buried dislocations. The general treatment for the diffusion of Co adatoms and growth on the strained Pt surface is given as a prototype for magnetic recording media. Ab initio self-consistent calculations of surface diffusion events of a Co adatom on the Pt(111) surface show that adatoms prefer to diffuse to the regions of largest tensile strain. The hopping barrier for adatom diffusion increases with tensile strain showing that preferred nucleation occurs in the regions of high tensile stress. The variation of the hopping barrier on the underlying strain produced by buried dislocations is analyzed in terms of a surface stress relief picture based on ab initio calculations. Based on these results, kinetic Monte Carlo studies of the growth of Co on Pt(111) have been performed; they show the possibility of controlled growth of patterned nanostructures with appropriate choice of dislocation spacing, film thickness and temperature.