PULSES AND DISORDER IN A CONTINUUM VERSION OF STEP-BUNCHING DYNAMICS

Starting from the Burton-Cabrera-Frank model in the presence of electr omigration, we derive a nonlinear continuum version of step dynamics, whew steps undergo a bunching instability. The obtained equation for t he steps density is a mixture of the Korteweg-de Vries equation, which leads to solitons, and the Burger equation, which exhibits spatiotemp oral chaos. For a small dispersive term, spatiotemporal chaotic pulses prevail. On increasing this term, we observe gradually a transition t owards regular pulses.