Structure and stability of Sb / Au ( 110 ) - c ( 2 · 2 ) surface phase

Adsorption of 0.5 monolayers (ML) of Sb on the Au(110) surface resulted in the formation of a c(2 · 2) surface reconstruction. Analysis of surface X-ray diffraction data by a direct method revealed the existence of an ordered substitutional surface alloy, with every other hollow site occupied by Au and Sb atoms. Quantitative conventional v refinement showed a contraction of 0.12 ± 0.03 Å in the spacing of the first Au layer to the second, an expansion of 0.13 ± 0.03 Å in the second-to-third layer distance, and an inward Sb displacement (rumpling) of 0.21 ± 0.04 Å. This surface phase proved to be extremely robust, with the long-range order of this arrangement remaining up to substrate temperatures of 900 K. 2005 Elsevier B.V. All rights reserved.