Surface structures of CuAu and CuPd alloys as observed by leed

Abstract

Surface structures are studied by LEED in Cu−Au and Cu−Pd alloy systems and compared with those expected from the bulk ordered structures of Cu 3Au(Cu 3Pd(α′)), CuAuI and CuPd(β). The c(2×2) structure on the {100} surface of CuAu and CuPd systems seems to agree with the sections of Cu 3Au and Cu 3Pd(α′), respectively. The (2×1) structure on the {110} surface of CuPd system has the same periodicity as that in the section of Cu 3Pd(α′) and the (2×2) structure on the {111} surface of CuAu system is considered to correspond to the section of the CuAuI structure. Characteristic surface structures such as (1×2), complex, c(3×1), and (2×2) on the {110} surface and ( 2 3 √3 × 2 3 √3 )R30° on the {111} surface are observed for the CuAu system, which are not expected from the sections of the bulk ordered structures.