Regensburg 2013 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 58: Poster Session III (Solid-liquid interfaces; Scanning probe and other methods; Electronic structure theory; Spin-orbit interaction)

O 58.31: Poster

Mittwoch, 13. März 2013, 18:15–21:45, Poster B1

Electronic lifetimes in a 2D electron gas in Bi/Cu(111): Screening effects and consequences for the spin structure — •Svenja Vollmar, Andreas Ruffing, Sebastian Jakobs, Alexander Baral, Steffen Kaltenborn, Mirko Cinchetti, Stefan Mathias, Martin Aeschlimann, and Hans Christian Schneider — University of Kaiserslautern

We compare energy resolved lifetimes in the quantum-well system Bi/Cu(111) as obtained from time- and angle-resolved 2-photon photoemission spectroscopy with the results of a Rashba model for the quantum-well bands with parameters extracted from the experiment.

Since the bulk screening constants for Bi and Cu are very different, we derive the correct statically screened potential for the Coulomb interaction of the electrons in the Bi-layer on the Cu-substrate.

We find that the measured lifetimes plateau around the intersection point cannot even qualitatively be explained on the basis of the Rashba model. Only by the ad-hoc introduction of a more complicated spin structure by assuming a k-dependent spin mixing, the calculated lifetimes qualitatively agree with experiment. Our results indicate that the spin-orbit coupling leads to band-structure effects beyond those described in a pure Rashba model.