Regensburg 2010 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 41: Poster Session I (Semiconductor Substrates: Epitaxy and growth; Semiconductor Substrates: Adsorbtion; Semiconductor Substrates: Solid-liquid interfaces; Semiconductor Substrates: Clean surfaces; Oxides and insulators: Epitaxy and growth; Oxides and insulators: Adsorption; Oxides and insulators: Clean surfaces; Organic, polymeric and biomolecular films - also with adsorbates; Organic electronics and photovoltaics, Surface chemical reactions; Heterogeneous catalysis; Phase transitions; Particles and clusters; Surface dynamics; Surface or interface magnetism; Electron and spin dynamics; Spin-Orbit Interaction at Surfaces; Electronic structure; Nanotribology; Solid/liquid interfaces; Graphene; Others)

O 41.14: Poster

Dienstag, 23. März 2010, 18:30–21:00, Poster B1

Coexistence of forward and backward buckled π-bonded chains on the Si(111)-2×1 surface — •Thomas K. A. Spaeth, Martin Wenderoth, Karolin Löser, and Rainer G. Ulbrich — IV. Physikalisches Institut, Georg-August Univ. Göttingen, Germany

The (2×1) reconstructed Si(111) surface, prepared by cleaving in ultra-high vacuum, has been studied for more then forty years. Different models for the description of this basic reconstruction have been proposed. The model of π-bonded chains is widely accepted, but it is still an open question whether forward or backward buckled chains are formed. This ambiguity is due to the small energetic difference between the two variants. Even though the STM cannot directly distinguish between forward and backward buckled π-bonded chains, we find indications of the coexistence of both chain types by analyzing anti-phase-boundaries between domains of given buckling type on the Si(111)-2×1 surface. The anti-phase-boundaries show a lateral shift of the π-bonded chains which is not compatible with a model of only one type of buckling. But it can be readily explained by "colliding" domains of differently buckled chains. This finding is supported by STS data taken across the anti-phase-boundaries. They show different electronic structures on both sides. We acknowledge financial support by the DFG via project WE 1889/3.