JOURNAL-OF-CRYSTAL-GROWTH. MAR 1999; 199 Part 1 : 22-26

Kinetic roughening is not a phase transition and, as such, it lacks a sharp definition. Therefore, the many criteria used to mark the onset of kinetic roughening, are expected to give different results. Criteria stemming from the classical two-dimensional nucleation theory are frequently used. Experimentalists, on the other hand, observe a transition from flat to rounded crystal facets at certain driving forces, or measure the growth rate as a function of the driving force and find a change from exponential to linear growth kinetics. It is assumed that these experimental phenomena coincide with the onset of kinetic roughening. In this paper, the extent of the differences between these criteria is investigated by means of Monte Carlo simulations on a Kossel (1 0 0) SOS model. The four criteria studied yield different values for the critical driving force, although three of them show a similar, almost linear, dependence of the critical driving force on the nearest-neighbor bond strength.