Effect of strong surface anisotropy on morphology of periodic surface profiles Original Research Article

Flattening of corrugated crystal surface has been studied for the case when mass transport is driven by surface diffusion and the surface itself is strongly anisotropic. In the approach adopted in the study, the orientation of initial, non-perturbed surface corresponds to the deep singular cusp on the otherwise spherical surface energy γ-plot. A system of non-singular differential equations describing the temporal evolution of corrugated surface in the small slope approximation has been formulated. The approximate analytical solution of these equations for the case of slow diffusivity along the singular surface has been found with the help of perturbation theory. It demonstrates that the time for complete smoothening of the corrugation is finite, in sharp contrast with the previous treatments of the problem. For the long annealing times, the amplitude of corrugation decreases with time, t, according to the a−bt0.25 law, where a and b are constants. The process of the nucleation of a facet at the initial stages of the annealing is also discussed.