Relaxation of a grooved profile cut in a crystalline surface of high symmetry

The smoothing of artificial grooves on a high-symmetry crystal surface below its roughening transition is investigated in the light of a one-dimensional model. In the case of diffusion dynamics, a new, kinetic, attractive interaction between steps opposes the contact repulsion and tends to flatten the top and the bottom of the profile in the transient state anterior to complete smoothing. This phenomenon, which is absent from continuum models, is weaker, but still present in real, two-dimensional surfaces. Kinetic Monte Carlo simulations have been performed for large modulation amplitudes in contrast with previous works. The relaxation time tau scales with the wavelength lambda as tau proportional to lambda(3) for diffusion dynamics and as tau proportional to lambda(2) for evaporation dynamics. In the case of evaporation dynamics, the transient profile is sinusoidal. In the case of surface diffusion the profile presents blunted parts at the top and at the bottom, which result from the kinetic attraction between steps.