Static lattice distortions and the structure of Au/Si(111)-(51): An x-ray-diffraction study
b'Grazing-incidence x-ray diffraction has been used to determine the atomic arrangement in the 5\\xd71 structure of Au on Si(111). The main features of this structure are partially occupied rows of gold atoms in low-symmetry sites. The density of Au atoms is highly asymmetric in the direction perpendicular to the rows. The substrate atoms in the top double layer are shifted up to 1 \\xc5 from their bulk position. The structure has a disordered 5\\xd72 periodicity due to the variation of the interatomic Au-Au distances within a row in the [011\\xaf] direction. The model is consistent with recent scanning-tunneling-microscopy topographs.'