Abstract
The activation barriers against adatom migration on terraces and across steps play an essential role
in determining the growth morphology of surfaces, interfaces, and thin �lms. By studying a series of
adatoms on representative transition metal surfaces through extensive �rst-principles calculations,
we establish a clear correlation between the preferred mechanism and activation energy for adatom
descent at a step and the relative degree of electronic shell �lling between the adatom and the
substrate. We also �nd an approximate linear relation between the adatom hopping barriers at step
edges and the adatom-surface bonding strength. These results may serve as simple guiding rules
for predicting the precise atomic nature of surface morphologies in heteroepitaxial growth such as
nanowires.