Structural analysis of the Cu(100)–p(3)R45°–Sn surface using low and medium energy ion scattering spectroscopies

The atomic structure of the Cu(100)–p(3 2 × 2 )R45°–Sn surface has been studied using medium energy ion scattering (MEIS), co-axial impact collision ion scattering spectroscopy (CAICISS), low energy electron diffraction (LEED) and Auger electron spectroscopy (AES). The p(3 2 × 2 )R45° reconstruction was observed with LEED following the deposition of 0.42 ML of Sn from a Knudsen cell on to the clean Cu(100) surface. The existence of sub-surface Sn atoms was immediately ruled out by the lack of blocking dips in the MEIS Sn scattered yield. Previously reported Sn overlayer and Cu–Sn surface layer alloy models were tested against the medium and low energy ion scattering data, with the best fit realised following structural optimization of the surface alloy model proposed by Pussi [K. Pussi et al., Surf. Sci. 549 (2004) 24]. Different out-of-plane shifts were observed for Sn atoms depending on their proximity to the missing Cu row.