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

The surface stress and energetics of the clean-, Sb-adsorbed-, and Sb-interdiffused-Ge(0 0 1) surfaces have been calculated using the ab initio density functional method. It is found that interdiffusion of Sb into deeper layers of Ge(0 0 1) leads to a more isotropic surface stress but corresponds to a higher total energy configuration. As a result of competition between stress relief and energy gain, the surface with all the Sb atoms adsorbed on the top of Ge(0 0 1) surface layer is predicted to have a less ordered geometry.