Abstract
When a heteroepitaxial film is grown on a vicinal substrate, the terrace steps at the growth front may bunch together to relieve strain, resulting in a rough surface. On the other hand, proper manipulation of the growth kinetics may suppress the inherent bunching instability, thus preserving step-flow growth. Here we show that the dispersion relation of the step dynamics in the early stages of growth can already determine whether the bunching instability is truly suppressed, prior to bunching actually takes place in the unstable regime. We determine the critical film thickness above which steps will bunch, and exploit its scaling properties and usefulness for extracting intrinsic energy parameters. Experimental results of SrRuO3 films grown on vicinal SrTiO3 substrates support qualitatively these predictions.
