Regensburg 2016 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 18: Metallic Nanowires on Semiconductor Surfaces
O 18.4: Poster
Montag, 7. März 2016, 17:00–19:30, Poster A
Local defects in quasi-1D Si(553)-Au — •Zamin Mamiyev, Timo Lichtenstein, Christoph Tegenkamp, and Herbert Pfnür — Institut für Festkörperphysik, Leibniz Universität Hannover, Germany
Self-assembled quasi-1D metallic structures formed on vicinal Si surfaces are highly attractive due to their individual electronic states that are confined to a single spatial dimension. In this respect, metallic nanowires induced by Au atoms at the regularly stepped Si(553) surface exhibit a variety of interesting electronic properties which are determined by the atomic structure. In order to obtain a quantitative description of the chemically adsorbed residual gas (CO, H2O, H2) effect to plasmon loss, time dependent electron energy loss spectra were measured along the momentum transfer parallel (q||) and perpendicular (q⊥) to wires. Plasmon loss energy shows a linear decay of the adsorption probability as a function of active site concentration, and an exponential saturation of the additional coverage with time.
On the Si(553)-Au surface Au atoms are arranged in dimerized double chains per terrace and show a strong tendency to suffer structural transitions. Since the whole terrace is chemically active on the Si(553)-Au surface, it is conceivable that an adsorption of the additional atoms takes place on these chains. Due to strong chemical bonds, atomic hydrogen locally converts the Au chains into an insulator. Therefore, the atomic hydrogen adsorbed on the surface is limiting the propagation of collective modes.