  We demonstrate, using well-established nonequilibrium limited-mobility
solid-on-solid growth models, that mound formation in the dynamical surface
growth morphology does not necessarily imply the existence of a surface edge
diffusion bias (the Schwoebel barrier). We find mounded morphologies in several
nonequilibrium growth models which incorporate no Schwoebel barrier. Our
numerical results indicate that mounded morphologies in nonequilibrium surface
growth may arise from a number of distinct physical mechanisms, with the
Schwoebel instability being one of them.
