Anomalous roughness in dimer-type surface growth

We point out how geometric features affect the scaling properties of nonequ ilibrium dynamic processes, by a model for surface growth where particles c an deposit and evaporate only in dimer form, but dissociate on the surface. Pinning valleys (hilltops) develop spontaneously and the surface facets fo r all growth (evaporation) biases. More intriguingly, the scaling propertie s of the rough one dimensional equilibrium surface are anomalous. Its width , W similar to L-alpha, diverges with system size L as alpha = 1/3 instead of the conventional universal value alpha = 1/2. This originates from a top ological nonlocal evenness constraint on the surface configurations.