Regensburg 2013 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 55: Electronic Structure and Spin-Orbit Interaction II
O 55.1: Vortrag
Mittwoch, 13. März 2013, 16:00–16:15, H42
Hexagonal warping effects in the spin-split electronic structure of the BiAg2 surface alloy — •Hendrik Bentmann1,2, Mattia Mulazzi1,2, and Friedrich Reinert1,2 — 1Experimentelle Physik VII, Universität Würzburg, D-97074 Würzburg, Germany — 2Gemeinschaftslabor für Nanoanalytik, Karlsruher Institut für Technologie KIT, D-76021 Karlsruhe, Germany
Whereas the Rashba-model predicts an isotropic spin-orbit (SO) splitting and an in-plane spin orientation for the electronic states in a two-dimensional electron gas (2DEG), the anisotropic lattice symmetries in a real system can lead to significant deviations from this scenario. Based on angle-resolved photoemission experiments, we discuss such effects for the surface states of the BiAg2 surface alloy, a prototype model system for SO effects in 2DEGs. The dispersion of the surface states shows a pronounced hexagonal warping which is accurately captured by k·p-theory taking into account the C3v-symmetry of the surface. Additionally, we find threefold modulations in the photoemission intensity giving hints on the influence of the lattice symmetry on the orbital character of the electronic states. We compare our results on BiAg2 with similar effects in the surface electronic structure of the topological insulator Bi2Te3(0001).