The precise microscopic origin of step meandering was not known in many real situations. A detailed study of this instability was made for copper, and none of the microscopic mechanisms proposed until now was able to describe all of the observed characteristic features of the instability, in particular, its dependence on the crystallographic orientations of steps. A novel scenario was proposed and, using kinetic Monte Carlo simulations, it was shown that essentially all of the features of step meandering of Cu could be explained if atoms diffused along step edges and freely turn around the kinks which they encountered along the ledge. In a counter-intuitive way, step-meandering then appeared to be due to the very mechanism (step-edge diffusion) that was expected to oppose it.

When Smoothening Makes it Rough - Unhindered Step-Edge Diffusion and the Meandering Instability on Metal Surfaces. F.Nita, A.Pimpinelli: Physical Review Letters, 2005, 95[10], 106104 (3pp)