Adsorption of sulfur on Ag(100)

We have used scanning tunneling microscopy and density Functional theory to investigate the structures formed by sulfur on Ag(100). As indicated by previous low-energy electron diffraction studies, the main phases have unit cells of p(2 × 2) and (√17 × √17)R14°. We show that the latter is a reconstruction. The favored structural model is one in which 5 Ag atoms are missing from the (100) surface plane per unit cell. The ejected Ag atoms combine with sulfur to form islands of the reconstructed phase on the terraces. The (√17 × √17)R14° phase coexists with the p(2 × 2), at sulfur coverages slightly above 0.25 monolayers. In addition, chain-like structures are observed in STM, both at room temperature (where they are dynamic) and below (where they are not). These results are compared with relevant literature for copper surfaces.