Pussi, K;AlShamaileh, E;McLoughlin, E;Cafolla, AA;Lindroos, M

2004

January

Surface Science

Determination of the structure of Cu {100}-p(3 root 2)R45 degrees-Sn by dynamical LEED

Published

28 ()

METAL MONOLAYERS SURFACE ALLOY LEAD CU(100) COPPER LAYERS PHASE TIN

549

24

30

The geometrical structure of 0.50 ML Sn adsorbed on Cu {100} surface has been studied using Symmetrized Automated Tensor LEED. At this coverage, a p(3root2- x root2-)R45degrees ordered surface structure is formed. The favoured structure is a substitutional surface alloy, that includes a missing row reconstruction. This structure might have originated a from c(2 x 2) superstructure. The p(3root2- x root2-)R45degrees phase is formed by bringing pairs of Sn atoms together in the Cu{100} -c(2 x 2)-Sn alloyed top layer and removing every third row of copper in the top layer. The two in-equivalent tin atoms in the first layer are buckled towards the solid-vacuum interface by 0.39/0.27 +/- 0.07 Angstrom with respect to the first layer copper atoms. The buckling between the Sn atoms is 0.12 +/- 0.08 Angstrom. The lateral displacement of Sn atoms is of magnitude 0.26 +/- 0.10 Angstrom. The first interlayer spacing is expanded by 4% with respect to the bulk value. Pendry reliability factor has been used to measure the level of agreement between theory and experiment giving a moderate value of 0.26 for the favoured structure. (C) 2003 Elsevier B.V. All rights reserved.

AMSTERDAM

0039-6028

10.1016/j.susc.2003.11.029