Role of codeposited impurities during growth. I. Explaining distinctive experimental morphology on Cu(0 0 1)

A unified explanation of the physics underlying all the distinctive features of the growth instabilities observed on Cu vicinals has long eluded theorists. Recently, kinetic Monte Carlo studies showed that codeposition of impurities during growth could account for the key distinctive experimental observations. To identify the responsible impurity atom, we compute the nearest-neighbor binding energies (E_NN) and terrace diffusion barriers (E_d) for several candidate impurity atoms on Cu(0 0 1) using DFT-based VASP. Our calculations show that codeposition (with Cu) of midtransition elements, such as Fe, Mn, and W, could-in conjunction with substantial Ehrlich-Schwoebel barriers-cause the observed instabilities; when the experimental setup is considered, W emerges to be the most likely candidate. We discuss the role of impurities in nanostructuring of surfaces.