Theory for the hexagonal reconstruction of fcc(100) surfaces of metals

Abstract

Reconstructions at the (100) surface of Ir, Pt and Au are determined by applying the Novaco-McTague model to a contracted hexagonal top layer of surface atoms. The top layer of atoms is approximated by a two-dimensional isotropic continuum influenced by the substrate potential. Assuming that the Fourier components of the substrate potential stabilizing the (5 × 1) structure play a dominating role, it is shown that the Pt(100) top layer lattice is in a particular direction uniaxially incommensurate with the substrate lattice and that the Au(100) surface layer is in two directions incommensurate. The calculated rotation angles for the top layer are in agreement with the ones observed for the Pt(100) and Au(100) surface.