Ab initio study of the one-monolayer Sb/Si(0 0 1) interface

Ab initio calculations, based on norm-conserving pseudopotentials and density functional theory, have been performed to investigate the displacive Sb adsorption on the Si(0 0 1) surface with the (2 × 1) reconstruction. For the one-monolayer coverage of Sb, even though the formation of a pure Sb–Sb dimer is energetically more favorable than the interdiffusion of Sb into any of the second and third substrate layers, we found further that this interdiffusion will relieve the tensile stress along the dimer bond leading to an increasing isotropy in surface stress indicating that displacive adsorption might still be an intermediate step towards surface roughness.