Ab-initio study of Si(111) square root 3* square root 3-Sn using molecular dynamics total energy methods

An ab-initio relaxation of the Si(111) square root 3* square root 3-Sn structure is performed. The LDA total energy is minimized using the molecular dynamics method of Car and Parrinello (1985), with the inclusion of separable nonlocal pseudopotentials. The pseudopotential implementation is discussed in detail. Competing sites for the Sn adatom are investigated. Results agree well with recent X-ray diffraction experiments.