Regensburg 2016 – scientific programme

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O: Fachverband Oberflächenphysik

O 29: Topology- and Symmetry-Protected Materials

O 29.4: Talk

Tuesday, March 8, 2016, 11:30–11:45, S051

Time- and angle-resolved two-photon photoemission from p-doped septuple-layered topological insulators — •Sebastian Otto, Jonas Rietsch, 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 of septuple-layered antimony telluride crystals of different p-dopings. All surfaces show a topological surface state. The Dirac point is found between E_F + 0.38 eV for GeSb₂Te₄ and E_F + 0.25 eV for SnBi_0.2Sb_1.8Te₄. The topological surface state is populated mainly from the conduction band minimum according to the evolution of its temporal population. Similar to the case of SnSb₂Te₄ [1], the electrons in the topological surface state decay rather fast into a partially unoccupied valence band maximum depending on the strength of the p-doping.
[1] D. Niesner, S. Otto, V. Hermann and Th. Fauster, Phys. Rev. B 89, 081404(R) (2014)