Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5424728 | Surface Science | 2008 | 5 Pages |
The dispersion of quasi-one-dimensional dangling-bond electrons in Ï-bonded chains at the Si(1Â 1Â 1)-2Â ÃÂ 1 and Ge(1Â 1Â 1)-2Â ÃÂ 1 surfaces has been experimentally investigated by angle-resolved photoemission spectroscopy, in the direction perpendicular to the chains, with a high energy and angle precision. The results show a very small dispersion in the case of Si(1Â 1Â 1)-2Â ÃÂ 1 and instead a much larger (downward) dispersion (156Â meV) in the case of Ge(1Â 1Â 1)-2Â ÃÂ 1. Accurate density-functional calculations with GW corrections are in very good agreement with the experimental results. Then the surface chains are somewhat interacting in Ge(1Â 1Â 1)-2Â ÃÂ 1 - the coupling occurring mainly through the subsurface region - while in Si(1Â 1Â 1)-2Â ÃÂ 1 they are essentially decoupled. Therefore the one-dimensional character of electrons in surface chains is enhanced in Si(1Â 1Â 1)-2Â ÃÂ 1 with respect to Ge(1Â 1Â 1)-2Â ÃÂ 1.