Bismuth on copper (110): analysis of the c(2 × 2) and p(4 × 1) structures by surface X-ray diffraction

Abstract

Surface X-ray diffraction has been used to analyze the atomic structures of the Cu(110)-c(2 × 2)Bi and Cu(110)-p(4 × 1)Bi reconstructions with submonolayer coverages. A quasi-hexagonal c(2 × 2) adlayer structure is formed when half a monolayer of bismuth is deposited; the coverage corresponds to 1.08 × 10 −15 atoms cm −2. There is one Bi atom per c(2 × 2) surface unit cell, and the nearest-neighbor distance on the planar overlayer was found to be 4.43 Å. In the case of the p(4 × 1) reconstruction formed at a coverage of 0.75 monolayers, both the in-plane and out-of-plane data are in excellent agreement with a model in which every fourth Cu row in the [001] direction of the topmost layer is replaced by Bi atoms to form a substitutional surface alloy.