Monomer aggregation model for DLA dendrite crossover

We consider Monte Carlo simulation of monomer aggregation into clusters with a view to simulate both DLA and dendrites. We introduce a new method of suppressing fluctuations by allowing two types of relaxations. First is a local on-site relaxation of monomers and the second, diffusive relaxation of the monomers along the perimeter of the cluster. The former is characterized by two energies and the latter by two activation energies corresponding to diffusion along edges and diffusion motion which is transverse locally. The model produces both DLA- and dendrite-like patterns for different choices of parameters. We find two distinct configurations of dendrites corresponding to two distinct anisotropic directions.