ANISOTROPIES IN AGGREGATES WITH BIASED RANDOM-WALKS ON 2-DIMENSIONAL LATTICES

Irreversible stochastic models of growth in which particles are global ly biased to seed are formulated and studied by Monte Carlo simulation s on triangular, hexagonal, and square lattices. In the deterministic aggregation model (DAM), where only the effect of attraction between p articles and the seed is considered, the particles have peculiar paths of motion on each lattice. Aggregates with biased random walks manife st special anisotropies on the two-dimensional lattices which are the same as those in DAM's. We discuss the universal and nonuniversal prop erties of these aggregates on the two-dimensional lattices.