A consistent interpretation of the atomic and electronic structure of the Si(111)−7×7 surface

A simple mechanism leading to the 7×7 reconstruction of the Si(111) surface is proposed. In this model a charge-density wave with the 7×7 pattern acts as the driving force which precipitates the dehybridisation of the surface atoms. The atoms at the surface form terraces of height ～0.3 Å. This small corrugation of the surface gives rise to a much larger (～3 Å) corrugation of the charge in agreement with recent He atom scattering experiments. The model is also in qualitative agreement with photoemission, optical absorption and ion scattering experiments.