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 44.46: Poster

Mittwoch, 28. März 2007, 17:00–19:30, Poster C

Spin-Orbit Induced Valence-Band Splitting in Mg Thin Films Grown on W(110) and Mo(110) — •Alexander Gottberg, Alexander Helmke, Victor Soltwisch, Günter Kaindl, and Eugen Weschke — Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany

Due to the comparably long penetration depth of its wave function into the bulk [1], the Shockley-like Mg(0001) surface state is strongly influenced in thin films by the substrate. The surface-state band is known to interact with an interface resonance formed at the substrate. This interaction gives rise to a parity-induced energy splitting that depends on the Mg film thickness [2].

Using high resolution angle-resolved photoelectron spectroscopy a second, thickness-independent splitting is observed in Mg/W(110) that is absent in case of Mg/Mo(110). This comparison supports the interpretation of this additional splitting in terms of a Rashba-like spin-orbit effect induced by the W substrate. Since spin-orbit effects scale with the atomic number, this splitting is supposed to be weak in case of Mo, which is in agreement with the experiment.

[1] T. K. Kim et. al. Phys. Rev. B 72, 075422 (2005)

[2] F. Schiller et. al. Phys. Rev. B 95, 126402 (2005)