Morphologies in two-dimensional growth with attractive long-range interactions

A two-dimensional growth model is introduced in which the morphology of aggregates depends on long-range two-body attractive interactions with a potential of the kind U(r)=C/ra. Its relation with continuum diffusive models is discussed. The morphology changes are studied for clusters of 2000 particles as a function of the potential parameters p=C/kBT<0 and a. The effect of anisotropy is taken into account by letting particles diffuse and aggregate on a triangular lattice. Tip-splitting occurs for small |p| and large a. The cluster scaling and symmetry properties are investigated in connection with the morphology transitions.