Regensburg 2007 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 17: Poster Session I (Nanostructures at Surfaces; Metal Substrates: Epitaxy and Growth; Methods: Scanning Probe Techniques; Phase Transitions)

O 17.7: Poster

Montag, 26. März 2007, 17:30–20:30, Poster C

Ab initio study of electronic confinement on stepped Cu(111) surfaces — •Pavel Ignatiev¹, Valeriy Stepanyuk¹, Andriy Klavsyuk¹, Wolfram Hergert², and Patrick Bruno¹ — ¹Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany — ²Fachbereich Physik, Martin-Luther-Universität, Halle-Wittenberg, Friedemann-Bach-Platz 6, D-06099 Halle, Germany

We report on study of surface states on clean and decorated Cu(111) stepped surfaces by means of ab initio Korringa-Kohn-Rostoker (KKR) Green's function method [1]. Surfaces with the terrace width ranging from 12 to 21 A are considered. Confined electronic states are revealed close to the Fermi energy. This finding is in agreement with experiments of M. Hansmann et al. [2]. Our calculations confirmed that the position of such states strongly depends on the terrace width. The strength of the potential barrier at the step edges calculated using the Kronig-Penney model and our ab initio results is found to be in a good agreement with experimentally determined values. It is shown that the strength of the confining barriers on Cu(111) vicinals can be significantly affected by decoration of step edges with monoatomic Fe wires, similar to recent experimental finding of S. Shiraki et al. [3]. Due to spin-dependent scattering of surface-states electrons at Fe wires surface states become spin-polarized. The majority states remain unaffected, but the confinement picture of the minority states is suppressed by a strong scattering of surface-states electrons at the minority states on Fe wires. [1] P.A. Ignatiev et al., submitted to PRB [2] M. Hansmann et al. PRB 67, 121409 (2003) [3] S. Shiraki et al. PRL 92, 096102 (2004)