F. Gutheim, H. Müller-Krumbhaar, and E. Brener

Heteroepitaxial growth of clusters in presence of elastic strain has been studied by means of a multi-grid Monte Carlo simulation. Deformation of the underlying substrate typically leads to a repulsive 1/r**3 interaction-potential between the adsorbed atoms. We find an increased effective fractal dimension df on small scales, exhibiting a crossover to the conventional dimension of diffusion limited aggregation (DLA) on large scales. We show that the growth velocity of an advancing fractal step grown from a lattice gas of finite density refiects this crossover phenomenon and is linked to the fractal dimension of the aggregate by through the matching of length-scales.