Regensburg 2007 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 44: Poster Session II (Semiconductors; Oxides and Insulators: Adsorption, Clean Surfaces, Epitaxy and Growth; Surface Chemical Reactions and Heterogeneous Catalysis; Surface or Interface Magnetism; Solid-Liquid Interfaces; Organic, Polymeric, Biomolecular Films; Particles and Clusters; Methods: Atomic and Electronic Structure; Time-resolved Spectroscopies)
O 44.42: Poster
Mittwoch, 28. März 2007, 17:00–19:30, Poster C
Spin- and momentum-resolved (inverse) photoemission for in situ investigation of the electronic structure of magnetic thin films — •Michael Budke, Tobias Allmers, and Markus Donath — Physikalisches Institut, Wilhelm-Klemm-Str. 10, 48149 Münster
We present a combined experimental set-up for spin- and momentum-resolved photoemission (PE) and inverse photoemission (IPE). This unique combination allows the investigation of the electronic structure below and above the Fermi level EF of magnetic materials in one chamber on the same sample preparation. The system for PE is commercially available and consists of a gas discharge lamp and an electron analyzer equipped with a SPLEED detector for spin-resolved measurements. Our spin-resolved IPE system is home-made and consists of a spin polarized electron gun and a Geiger-Müller tube filled with acetone vapour for photon detection. The main advantage of our IPE system is its superior energy resolution of 165 meV (FWHM). This is a factor of two better than other state-of-the-art set-ups for IPE and enables us to resolve narrow spectral features not seen before, especially close to EF. First results will be shown, which demonstrate the improved energy resolution in IPE on the Cu(001) image-potential states. The angular resolution is demonstrated on the surface state of Cu(111). In addition, the advantage of the in situ investigation of the electronic structure below and above EF will be shown on the system Cr(001) which has been discussed intensely due to a peak right at EF, previously interpreted as an orbital Kondo resonance [1]. [1] Kolesnychenko et al., Nature 415, 507 (2002)