Dresden 2011 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 5: Spin-Orbit Interaction at Surfaces I
O 5.1: Vortrag
Montag, 14. März 2011, 11:15–11:30, WIL B321
Topologically trivial and non-trivial states at the surface of Bi2Se3 — •Hadj Mohamed Benia, Klaus Kern, and Christian R. Ast — Max-Planck-Institut für Festkörperforschung, 70569 Stuttgart, Germany
Angle Resolved Photon Emission Spectroscopy (ARPES) measurements at the surface of Bi2Se3 single crystals show the existence of Rashba spin-split quantum-well states (QWS) together with the known topological surface state around the Γ point. Up to three QWS with different Rashba-splitting are observed between the Fermi level and the Dirac point. The origin of the QWS is traced back to a formation of a 2D electron gas at the crystal surface as a result to downward bending of the conduction band. A shift to higher binding energies of the QWS accompanied with a change in the Rashba splitting is observed as function of time and temperature. A triangular potential is used to model the band bending, fit the QWS levels, and extract the corresponding potential asymmetry at the surface for various measurement conditions.