Structure and stability of the Si(001) c(4x4)-Sb surface

Results of low-energy electron diffraction, Auger electron diffraction, low-energy ion scattering, and ab initio pseudopotential studies of submonolayer coverages of Sb on the Si(001) surface indicate the existence of an ordered c(4x4)-Sb reconstruction between 0.2 and 0.3 ML. Analysis of the ion-scattering data from this surface suggests an overlaid above-row structure in which Sb dimers are situated directly above Si dimer rows. Ab initio pseudopotential calculations support this conclusion and confirm that such a uniform distribution of Sb ad-dimers only becomes stable for a very narrow coverage range around 0.25 ML.