Berlin 2005 – wissenschaftliches Programm
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O: Oberflächenphysik
O 21: Elektronische Struktur II
O 21.4: Vortrag
Samstag, 5. März 2005, 11:30–11:45, TU EB107
Role of the spin in quasiparticle interference — •Ph. Hofmann1, J. I. Pascual2,3, G. Bihlmayer4, Yu. M. Koroteev5,6, H.-P. Rust3, G. Ceballos3, M. Hansmann3, K. Horn3, E.V. Chulkov5, S. Blügel4, and P.M. Echenique5 — 1Institute for Storage Ring Facilities, University of Aarhus, Denmark — 2Institut für Experimentalphysik, Freie Universität Berlin — 3Fritz-Haber-Institut der MPG, Berlin — 4Institut für Festkörperforschung, Forschungszentrum Jülich — 5Donostia International Physics Center (DIPC), Basque Country, Spain — 6Institute of Strength Physics and Materials Science, Tomsk, Russia
Defects on metal surfaces are screened by the surrounding electron gas, leading to the formation of standing electron waves or, more correctly, quasiparticle interference patterns. These patterns can be observed by scanning tunneling microscopy, either for a very small tunneling voltage or in conductance images. A Fourier transformation of conductance images can therefore give valuable information about the electronic structure and Fermi surface of quasi two-dimensional systems. Here we show that even in non-magnetic systems the spin of the quasiparticles can have a profound effect on the interference patterns. On Bi(110), where the surface state bands are not spin-degenerate, the patterns are not related to the dispersion of the electronic states in a simple way. In fact, the features which are expected for the spin-independent situation are absent and the observed interference patterns can only be interpreted by taking spin-conserving scattering events into account.