Regensburg 2007 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 34: Methods: Atomic and Electronic Structure I
O 34.4: Vortrag
Dienstag, 27. März 2007, 16:30–16:45, H42
Enhanced Rashba spin-orbit splitting in Bi/Ag(111) and Pb/Ag(111) surface alloys — •Gustav Bihlmayer1, Stefan Blügel1, and Eugene Chulkov2 — 1Institut für Festkörperforschung, Forschungszentrum Jülich, D–52425 Jülich, Germany — 2Donostia International Physics Center, 20018 San Sebastian/Donostia, Basque Country, Spain
We present first-principles calculations of a (√3 × √3) R 30∘ Bi/Ag(111) surface alloy. This alloy has recently been investigated experimentally using angle-resolved photoemission spectroscopy [1]. We find that the surface state in the L projected bulk-bandgap shows a Rashba-type spin-orbit splitting which 3 times larger than what has been observed on a clean Bi(111) surface. We explain this large enhancement, which was also found in experiments, by the strong distortion of the surface state wavefunction which is caused by the substantial outward relaxation of the Bi atom. For comparison we report on a similar surface alloy, Pb/Ag(111), where the strong Rashba-type splitting is found in the calculations. Experimentally, the situation seems to be a bit more complicated due to a second, close-by surface state which was also observed. We discuss the dependence of the two-dimensional bandstructure on the surface corrugation and compare to the experimental findings [2].
[1] C. R. Ast et al. arXiv:cond-mat/0509509 (2005)
D. Pacilé et al. Phys. Rev. B 73, 245429 (2006)