Atomistic modeling of step formation and step bunching at the Ge(105) surface

We investigate possible step geometries on the rebonded-step reconstructed Ge(105) surface. We focus our attention on steps oriented along the [010] direction, which have been shown to play a key role in the pyramid-to-dome transition during Ge growth on Si(001). Using molecular dynamics simulations based on the Tersoff potential, we evaluate the step formation energy for several alternative structures. The step-bunching process is also analyzed, showing that one monolayer-high steps are likely to group into multistepped structures. Our results provide support for very recent experiments and modeling on the pyramid-to-dome transition in Ge/Si(001). (c) 2005 Elsevier B.V. All rights reserved.