Kinetic Roughening of Fe/Fe(100) Epitaxial Thin Films

Abstract

ABSTRACTWe model kinetic roughening during Fe(100) homoepitaxy, where the formation of mounds with selected slope has been observed. Our model incorporates irreversible nucleation and growth of two-dimensional square islands in each layer, and a step-edge barrier to diffusive downward transport (which exceeds the barrier, Ed, to terrace diffusion by ESch). We estimate that ESch≈45meV compared with Ed≈450meV. To reproduce observed behavior, it is also essential for the model to incorporate "downward funneling" of depositing atoms to four-fold hollow adsorption sites, as this controls slope selection. Finally, we discuss model predictions for the non-monotonic temperature dependence of kinetic roughening.