SMOOTHING OF ROUGH SURFACES

Simulations of surface smoothing (healing) by Langevin dynamics in lar ge systems are reported. The surface model is described by a two-dimsi onsional discrete sine-Gordon (solid-on-solid) equation. We study how initially circular terraces decay in time for both zero and finite tem peratures and we compare the results of our simulations with various a nalytical predictions. We then apply this knowledge to the smoothing o f a rough surface obtained by heating an initially flat surface above the roughening temperature and then quenching it. We identify three re gimes in terms of their time evolution, which we are able to associate with the resulting terrace morphology. The regimes consists of a shor t initial stage, during which small scale fluctuations disappear; an i ntermediate, longer time interval, when evolution can be understood in terms of terraces and their interaction; and a final situation in whi ch almost all terraces have been suppressed. We discuss the implicatio ns of our results for modeling rough surfaces.