Dresden 2014 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 62: Posters: Surface Reactions and Dynamics, Nanostructures

O 62.17: Poster

Mittwoch, 2. April 2014, 17:30–21:00, P1

Circular dichroism of the unoccupied topological surface state of SnSb₂Te₄ — •Sebastian Otto and Thomas Fauster — Lehrstuhl für Festkörperphysik, Universität Erlangen-Nürnberg, D-91058 Erlangen, Germany

Time- and angle-resolved two-photon photoemission is used to study the electronic structure and dynamics at the surface of SnSb₂Te₄. Circular dichroism is used to map the spin structure of the topological surface state. Due to the intrinsic p-doping the topological surface state is centered at 0.32±0.03 eV above the Fermi level with a group velocity of 3.4 eVÅ. The circular dichroism pattern of the Dirac cone shows a strong dependence on the polarization of the probe pulse while the polarization of the pump pulse has no significant effect. This stands in good agreement with time-resolved measurements showing a transient population of the topological surface state dominated by refilling from the conduction band minimum.