Regensburg 2013 – scientific programme
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O: Fachverband Oberflächenphysik
O 21: Electronic Structure and Spin-Orbit Interaction I
O 21.9: Talk
Monday, March 11, 2013, 18:00–18:15, H42
Spin-dependent unoccupied electronic structure of the topological insulator Bi2Se3: An inverse-photoemission study — •Anna Zumbülte1, Christian Langenkämper1, Anke B. Schmidt1, Markus Donath1, Tobias Förster2, Peter Krüger2, Marco Bianchi3, Richard Hatch3, Philip Hofmann3, Jianli Mi4, and Bo Brummerstedt Iversen4 — 1Physikalisches Institut, Universität Münster — 2Institut für Festkörpertheorie, Universität Münster — 3Department of Physics and Astronomy, Aarhus University — 4Department of Chemistry, Aarhus University
In recent years, topological insulators have become a focus of photoemission studies. Especially the spin-dependent electronic structure shows still surprising features, e.g. the evolution of Rashba-split quantum well states due to a strong surface band bending. With regard to possible devices and the interpretation of non-equilibrium behavior of topological insulators, the additional knowledge of their unoccupied electronic structure is essential.
In this talk, we present spin-resolved inverse-photoemission measurements on a prototypical topological insulator: Bi2Se3. While for higher energies bulk-derived features seem to dominate the obtained data, several features with distinct spin asymmetries are observable at energies up to 2 eV above the Fermi level. The nature of these will be discussed along with theoretical calculations including a long-ranged potential to simulate a band bending. In particular, these calculations predict an unoccupied W-shaped spin-split surface state which we observe experimentally at 1 eV above the Fermi level.