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TT: Fachverband Tiefe Temperaturen
TT 51: Topological Insulators (joint session DS, HL, MA, O, TT, organized by MA)
TT 51.6: Vortrag
Mittwoch, 22. März 2017, 16:30–16:45, HSZ 401
Lifetime and surface to bulk scattering of the topological surface state in 3D topological Insulators — •Philipp Rüßmann, Phivos Mavropoulos, and Stefan Blügel — Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich and JARA, D-52425 Jülich, Germany
Doping of topological insulators, such as Bi2Se3 or Bi2Te3, may result in a shift of the Fermi level to a position where the Topological Surface States (TSS) and the bulk states coexist. Then, the TSS lifetime τs due to impurity scattering is decomposed in surface-to-surface and surface-to-bulk contributions with scattering rates τss−1 and τsb−1, respectively, where τs−1=τss−1+ τsb−1. We investigate this decomposition in Bi2Se3 and Bi2Te3 by means of density-functional calculations.
In a detailed analysis we find that conduction and valence band play a different role in the surface to bulk state scattering. Especially for the important case of n-doping, the conduction band contribution is very small compared to the surface-state contribution. As a consequence, the surface electrons remain topologically protected in spite of coexisting bulk bands.
For the calculation of electronic structure and scattering properties we employed the full potential relativistic Korringa-Kohn-Rostoker Green-function method. We acknowledge financial support from the DFG (SPP-1666), from the VITI project of the Helmholtz Association and computational support from the JARA-HPC Centre at the RWTH Aachen University.