TEMPERATURE AND DISEQUILIBRIUM DEPENDENCE OF CLUSTER GROWTH

A growth model, in which the morphology of the clusters grown depends on temperature and disequilibrium, is presented. The model is a modified version of Kadanoff's pedestrian model. Sticking, rearrangement and evaporation compete with rates appropriate to the inverse temperature betaJ and to the disequilibrium beta DELTAmu. The relation between the simulations and the continuum thermal model is discussed, and the dependence of growth morphologies on the anisotropy epsilon is stressed. As temperature and disequilibrium increase the clusters become more and more branched. The same occurs to a lesser extent, for given temperature and disequilibrium, as time goes by. For 4 < betaJ < 5 a fairly well defined tip-splitting transition takes place from a dendritic to a dense branching morphology. The model correctly describes the behaviour of the growth velocity upsilon of a dendrite as a function of time. After a transient decrease, upsilon tends to a constant value. The model may be relevant for understanding domain growth in a lipid monolayer.