Berlin 2008 – scientific programme

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O: Fachverband Oberflächenphysik

O 55: Poster Session III - MA 141/144 (Methods: Atomic and Electronic Structure; Particles and Clusters; Heterogeneous Catalysis; Semiconductor Substrates: Epitaxy and Growth+Adsorption+Clean Surfaces+Solid-Liquid Interfaces; Oxides and Insulators: Solid-Liquid Interfaces+Epitaxy and Growth; Phase Transitions; Metal Substrates: Adsorption of Inorganic Molecules+Epitaxy and Growth; Surface Chemical Reactions; Bimetallic Nanosystems: Tuning Physical and Chemical Properties; Oxides and insulators: Adsorption; Organic, polymeric, biomolecular films; etc.)

O 55.7: Poster

Wednesday, February 27, 2008, 18:30–19:30, Poster F

Electronic structure of transition metal dichalcogenide misfit compounds — •Matthias Kalläne, Kai Roßnagel, and Lutz Kipp — Institute for Experimental and Applied Physics, University of Kiel, D-24098 Kiel, Germany

The incommensurate layered transition metal dichalcogenide (TMDC) misfit compounds are composed of alternatingly stacked slabs of hexagonally ordered TMDCs and cubic monochalcogenides, leading to a lattice mismatch in one direction parallel to the surface. In spite of the incommensurability, however, the slabs are in a very high stacking order perpendicular to the layers and the crystals show a high stability. In order to investigate the bonding perpendicular to the layers and the influence of the incommensurability on the electronic structure we have employed angle–resolved photoelectron spectroscopy on different TMDC misfit compounds. By studying the electronic structure at the Fermi surface, we could directly observe a charge transfer to the TMDC layers, while the electronic band dispersion perpendicular to the layers was found to be negligible. Therefore, the interlayer bonding seems to be dominated by ionic contributions, similar to intercalated TMDC compounds. To reveal possible incommensurability effects we have analyzed the band dispersion in different crystal directions and have found signatures of both subsystems in the electronic structure.

The photoemission experiments were carried out at the ALS in Berkeley. Work at the University of Kiel is supported by DFG Forschergruppe FOR 353.