Dresden 2009 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 48: Focused Session: Spin-Orbit Interaction at Surfafces: From the Rashba Effect to Topological States of Matter I
O 48.4: Vortrag
Donnerstag, 26. März 2009, 12:00–12:15, HSZ 02
Giant Rashba spin-orbit splitting in the unoccupied quantum-well band-structure of Bi/Cu(111) — •M. Aeschlimann1, S. Mathias1, A. Ruffing1, F. Deicke1, M. Wiesenmayer2, G. Bihlmayer3, E.V. Chulkov4,5, Yu.M. Koroteev4,6, and M. Bauer2 — 1Department of Physics and Research Center OPTIMAS, University of Kaiserslautern, 67663 Kaiserslautern, Germany — 2IEAP, Christian-Albrechts-Universität zu Kiel, 24908 Kiel, Germany — 3FZ Jülich, 52425 Jülich, Germany — 4DIPC, 20018 San Sebastián/Donostia, Spain — 5Departamento de Fisica de Materiales, UPV/EHU, Apdo 1072, 20080 San Sebastián, Spain — 6Institute of Strength Physics and Materials Science, RAS, 634021, Tomsk, Russia
The unoccupied electronic structure of the Bi surfactant layer (0.5 ML coverage) on Cu(111) is investigated by angle-resolved two-photon photoemission (AR-2PPE). An unoccupied quantum-well state is observed exhibiting a large spin-orbit splitted band with a Rashba energy of ER≃134 meV and a wave number offset of k=0.09 1/Å. This enhancement of the spin splitting is surprisingly high given the fact that the ultrathin Bi film on Cu(111) does not show surface alloying. We therefore carried out first principle calculations to unravel the origin of the large spin-splitting, potentially caused by corrugation or the influence of the interface potential onto the ultrathin Bi film, giving rise to a quantum-size induced giant spin-orbit splitting. Such a scenario would directly allow for another possibility to tailor spin-orbit splitting (next to surface alloying) by means of thin film nanofabrication.