Surface reconstructions of In on Si(111)

The complete phase diagram of In-induced surface reconstructions on Si(111) surfaces has been mapped by scanning tunneling microscopy (STM) and spectroscopy (STS). The spectroscopy results illustrate the transition from low-coverage semiconducting reconstructions via semimetallic phases to the metallic surfaces at monolayer coverages. Electronic effects in the STM imaging process preclude a straightforward interpretation of the STM data in terms of structure models for the surfaces at intermediate coverages, but for the higher-coverage metallic phases a topographic STM analysis is possible and detailed structure models are presented. The In-Si(lll) monolayer surfaces are interpreted in terms of regular adlayer structures above the first Si double layer, but discommensurate phases are observed in the presence of an external stress field, introduced by an external perturbation.