A Discrete Model for Nonequilibrium Growth Under Surface Diffusion Bias

A limited mobility nonequilibrium solid-on-solid dynamical model for kinetic surface growth is introduced as a simple description for the morphological evolution of a growing interface under random vapor deposition and surface diffusion bias conditions. Simulations using a local coordination dependent instantaneous relaxation of the deposited atoms produce complex surface mound morphologies whose dynamical evolution is inconsistent with all the proposed continuum surface growth equations. For any finite bias, mound coarsening is found to be only an initial transient which vanishes asymptotically, with the asymptotic growth exponent being 0.5 in both 1+1 and 2+1 dimensions. Possible experimental implications of the proposed limited mobility nonequilibrium model for real interface growth under a surface diffusion bias are critically discussed.