Regensburg 2010 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 76: Nanostructures at surfaces: Wires, tubes

O 76.5: Vortrag

Donnerstag, 25. März 2010, 16:00–16:15, H38

Ab-initio studies of Au-induced atomic wires on Ge(001) — •Simeon Sauer^1,2, Frank Fuchs¹, Friedhelm Bechstedt¹, Christian Blumenstein³, and Jörg Schäfer³ — ¹Institut für Festkörpertheorie und -optik, Universität Jena, D-07743 Jena — ²Physikalisches Institut, Universität Freiburg, D-79104 Freiburg — ³Physikalisches Institut, Universität Würzburg, D-97074 Würzburg

Au-induced atomic wires on Ge(001) are a promising model system to study the physics of one-dimensional electron liquids [1]. However, the results of scanning tunneling microscopy (STM) experiments do not permit to unambiguously determine the arrangement of surface atoms. Several questions remain unresolved: Are the observed protrusions formed by Au atoms only or do they incorporate Ge as well? What is their absolute height?

Therefore, we theoretically investigate possible atomic geometries of the surface in the framework of density functional theory. For each model, features like surface energy, STM images, and band structure are calculated. The computed properties are compared to experimental data and used to evaluate the different models. Due to the large variety of possible geometries no final statement about the atomic structure of the surface can be made. However, the calculations give good indications towards the correct geometry, e.g. ruling out models proposed in literature or identifying stabilizing building blocks [2].

[1] J. Schäfer et al., Phys. Rev. Lett. 101, 236802 (2008).

[2] S. Sauer, F. Fuchs, F. Bechstedt, C. Blumenstein, and J. Schäfer, submitted for publication.