Berlin 2005 – wissenschaftliches Programm

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O: Oberflächenphysik

O 41: Elektronische Struktur III

O 41.1: Vortrag

Dienstag, 8. März 2005, 10:45–11:00, TU EB107

Systematic ARPES study of the influence of different adsorbates on surface states — •Frank Forster, Azzedine Bendounan, Johannes Ziroff, Felix Schmitt, and Friedrich Reinert — Experimentelle Physik II, Universität Würzburg, Germany

On the example of the (111) surfaces of Cu, Ag and Au we demonstrate that high and angle resolved photoemission spectroscopy (ARPES)(Δ E=3 meV, Δ Θ=0.3^∘) is a powerful tool for the study of the influence of differnt absorption processes on the electronic structure of these systems.

We discuss that only one monolayer of weak-interacting rare gases is reponsible for a characteristic shift of the Shockley-states towards and even above the Fermi level whereas bulk states of the substrates remain – except for band back-folding – almost unimpressed. Furthermore, the Au(111) surface state experiences an increase in the spin-orbit splitting up to 30%.

In contrast to the physisorption process of rare gases, a coverage of alkali metals on the nobel metal surfaces leads to a opposite effect on the Shockley-states, i.e., a decrease of the still detectable spin-orbit splitting and an increase in binding energy, until they reach the bottom of the L-gap and vanish in the bulk states.

These experimental results are supported by theoretical considerations which allow a deeper understanding of the electronic processes on adsorbate-substrate interfaces.