Berlin 2008 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 18: Poster I : Bio Magn. (1-2); Mag.Imgaging (3-9); Magn. Semiconductors (10-16); Half Metals & Oxides (17-20); Coupl.Phenomena (21-27); Magn. Mat. (28-41); Micro & Nanostr. Magn. Materials (42-61); Micro Magn. (62-64); Surface Magnetism (65-70); Transport Phenomena (71-85)
MA 18.66: Poster
Dienstag, 26. Februar 2008, 15:15–18:30, Poster E
Spin-dependent surface electronic structure of Gd(0001) near the Fermi-level: An angle-resolved (I)PE study — •Michael Budke, Alexander Wittkowski, Juliet Correa, and Markus Donath — Physikalisches Institut, WWU Münster, Wilhelm-Klemm-Str. 10, 48149 Münster
A widely accepted picture for the surface electronic structure of Gd(0001) comprises a spin-split surface state (SS) with its mayority part 0.2 eV below EF and its minority part 0.5 eV above EF with a finite exchange splitting of 0.4 eV at TC [1]. The discussion about this SS remains controversially because spin-resolved inverse photoemission identified a SS with both minority and majority components above EF [2]. The reason for these conflicting results might be found in different sample conditions since the Gd films are usually grown on W(110), a material with considerably different lattice constant than Gd. To overcome this suspicion, we performed both, spin- and angle-resolved direct (PE) and inverse photoemission (IPE) on the same sample preparation of a 30 ML Gd film grown on Y(0001). We were able to identify two SSs with their minority and majority components well separated from EF. While the occupied SS shows spin-mixing behaviour as observed in other PE experiments, the unoccupied SS exhibits an exchange splitting of 250 meV that vanishes at TC. To identify the nature of the unexpected SS, we performed angular-resolved IPE measurements that support the interpretation as d-like SS above EF and reveal a variety of additional spectral features. [1] Getzlaff et al., JMMM 184, 155 (1998). [2] Donath et al. PRL 77, 5138 (1996).