Step-Adatom Attraction as a New Mechanism for Instability in Epitaxial Growth

Abstract
We show that short-range attraction of adatoms towards clusters and ascending steps leads to an instability towards mound formation in epitaxial growth. This instability is studied both analytically and via Monte Carlo simulations on bcc/fcc(100) surfaces. The origin of this instability in terms of second-layer nucleation and its implications for surface morphology and interpretation of recent experiments are also discussed.