Dresden 2006 – wissenschaftliches Programm

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O: Oberflächenphysik

O 14: Poster session I (Adsorption, Epitaxy and growth, Phase transitions, Surface reactions, Organic films, Electronic structure, Methods) (sponsored by Omicron Nanotechnology GmbH)

O 14.63: Poster

Montag, 27. März 2006, 18:00–21:00, P2

The Kondo-resonance in photoemission spectra on Ce and Yb thin-film systems — •Andreas Nuber, Markus Klein, Azzedine Bendounan, Frank Forster, and Friedrich Reinert — Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany

The physical properties of Kondo systems are determined by interaction between localized 4f states and conduction electrons which leads to a characteristic spectral resonance at the Fermi-level. This so called Kondo-resonance has been investigated thoroughly in the last two decades by various techniques, in particular on lanthanide systems [1]. The basis for a consistent understanding of these properties can be studied directly by angle resolved photoelectron spectroscopy (ARUPS). This requires highly-ordered single-crystalline surfaces that have to be prepared in situ by appropriate methods. For bulk single crystals this preparation can be rather troublesome. In order to get rid of these problems we have prepared thin film systems containing the rare-earth elements Yb and Ce by in situ evaporation. Our ARUPS results (res. ~3meV) show that these thin films and surface alloys have a long range order and can be used for a systematic study of band dispersions, crystal field effects and Kondo properties. We discuss the spectroscopic results in the framework of the Single Impurity Anderson model (SIAM) and compare the results with already existing data from bulk single crystals, with special respect to surface effects.

[1] Handbook on the Physics and Chemistry of Rare Earths, edited by K.A. Gschneidner, Jr.,L. Eyring and S. Hüfner, North-Holland, Amsterdam - New York - Oxford, 1982-2002