The structure of the Si(111)(√3 x √3)R30°-Sn surface determined using x-ray diffraction

Abstract

Abstract The structure of the ( 3 × 3 ) R 30° reconstruction induced by adsorption of 1 3 of a monolayer of Sn on the Si(111) surface has been determined using surface X-ray diffraction. The in-plane projection of the surface structure, obtained from structure factors near zero perpendicular momentum transfer, indicates substantial lateral displacements of the Si atoms. Intensity profiles of the fractional order rods give information concerning displacements normal to the surface. The adatoms are shown to occupy sites above second layer Si atoms. Incorporation of elastic strain minimisation into the structure factor analysis enables the identification of relaxations extending six layers into the bulk.