Stabilization of dense metallic Pb monolayer by decorating step edges with Au atoms on Si(111)

Abstract

Under specific conditions, the sequential growth of Au and Pb on Si(111) results in a huge modification of the surface structure which neither Au/Si nor Pb/Si growths provoke separately. Initially atomically flat 7x7 Si(111) substrate breaks into a terraced-hill structure containing up to 10 atomic terraces of a typical width 10-50 nm. Terraces are covered by a dense monolayer of Pb (nominal coverage 1.2 to 1.33 ML); their step edges are decorated by double rows of Au atoms. This could open a route for constructing superconducting Josephson devices on atomic scale.