The surface atomic structure of the p(2√2 x 4√2)R45° superstructure obtained at 0.5-monolayer coverage by deposition of germanium on the Ag(001) surface at room temperature was investigated using surface X-ray diffraction and scanning tunnelling microscopy. A structural model was proposed with clusters of four Ge atoms preferentially adsorbed near hollow and bridge sites on the surface. The Ge-Ag bond strength was sufficient to induce rearrangement of the Ag atoms in the uppermost layers and stabilize the reconstruction.

Ge Tetramer Structure of the p(2√2 x 4√2)R45° Surface Reconstruction of Ge/Ag(001) - a Surface X-Ray Diffraction and STM Study. H.Oughaddou, J.M.Gay, B.Aufray, L.Lapena, G.Le Lay, O.Bunk, G.Falkenberg, J.H.Zeysing, R.L.Johnson: Physical Review B, 2000, 61, 5692-7