Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5425068 | Surface Science | 2008 | 10 Pages |
Helium atom scattering (HAS) and scanning tunneling microscopy (STM) have been used to investigate five ordered phases formed by Sn-evaporation and deposition on room temperature Cu(0Â 0Â 1) surfaces. Complementary Auger (AES) and electron diffraction (LEED) studies have also been performed. Glide plane symmetry has been noted in a p(2Â ÃÂ 6) phase. The c(4Â ÃÂ 8), p(3â2Â ÃÂ â2), and c(4Â ÃÂ 4) phases exhibit measurable lateral relaxations. The c(4Â ÃÂ 8) and c(4Â ÃÂ 4) phases have Sn in distorted nearest-neighbor adsorption sites. New structural models are proposed for four Sn/Cu phases. Each of these models is discussed in light of the lateral stress relief mechanisms that are operative. STM topographic details are used to argue in favor of the prevalence of 2-D alloy-like structures in most phases. We speculate also on the necessity of subsurface vacancies in formation of the p2mg, p(2Â ÃÂ 6) ordered phase.