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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 14.62: Poster

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

Surface and quantum well states in Ag mono- and multilayers on Au(111): A high-resolution line-width study by ARPES — •Frank Forster, Eugen Gergert, Azzedine Bendounan, and Friedrich Reinert — Experimentelle Physik II, Universität Würzburg, Am Hubland 97074 Würzburg, Germany

Due to their strong localization on the (111) surfaces of noble metals Shockley states are a powerful tool for the study of different adsorption processes on theses systems. Furthermore they are suitable model systems for the investigation of many-body interactions like electron-electron, electron-phonon and electron-impurity scattering by angular resolved photoelectron spectroscopy (ARPES) (ΔE=3 meV, ΔΘ=0.3^∘). We present data on mono- and multilayers of Ag on Au(111). The ordered layer-by-layer growth allows a systematic study on the thickness dependence of the Ag layer on the surface electronic structure.

While the band mass of the spin-orbit split Au surface state increases with increasing Ag coverage, the binding energy and the Rashba term shift gradually to lower values. Additionally the line-width of the surface state becomes smaller although the density of defects on the surfaces increases. A further coverage of Ag generates new states in the bulk band gap of Au(111) with very narrow line-width.These quantum well states are confined in the Ag layer and show — like surface states — a quasi two-dimensional character with parabolic dispersion but a much smaller sensitivity on surface contamination.