MISSING ROWS ON OXYGEN-COVERED CU(100) VICINAL SURFACES - A SCANNING-TUNNELING-MICROSCOPY INVESTIGATION

Scanning tunnelling microscopy images of oxygen-covered Cu(410) facets , of the Cu(100)(root 2x2 root 2)R45 degrees-O structure, and of the f aceting of Cu(610) in the presence of adsorbed oxygen have been used t o investigate the basic elements of the atomic-scale structure of thes e surfaces. The existence of stable (100) nanofacets of widths corresp onding to those of(4n 1 0) (n = 2, 3,...) faces is shown to be consist ent with a common structural model for all of these surfaces based on the well known structural unit of three adjacent [001] Cu atom rows an d one missing row which comprises the Cu(100)(root 2x2 root 2)R45 degr ees-O surface. This model implies that on the (410) surface the missin g row lies at the bottom of each atomic step on this surface. All thes e structures have a common local geometry for the adsorbed O atoms coo rdinated to four Cu atoms.