Regensburg 2016 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 29: Topology- and Symmetry-Protected Materials
O 29.2: Vortrag
Dienstag, 8. März 2016, 11:00–11:15, S051
Mesoscopic spin coherence through electron focusing in topological insulators — •Philipp Rüßmann, Phivos Mavropoulos, Nguyen H. Long, and Stefan Blügel — Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich and JARA, D-52425 Jülich, Germany
Long coherence lengths of quasiparticles are an essential ingredient for spintronics applications. Motivated by previous experiments [P. Sessi et al, Nat. Comm. 5, 5349 (2014)] we undertook a combined theoretical and experimental study, using density functional theory and STM, where we found standing wave patterns of mesoscopic dimensions around magnetic defects on the surface of Bi2Te3. We identified two necessary conditions for the effect: (i) focusing by the Bi2Te3 Fermi surface due to its hexagonal warping and (ii) large scattering strength of the magnetic defects. We modeled different magnetic defects and analyzed the energy dependence of the scattering properties in the energy range where the shape of the constant energy contour changes from circular over hexagonal to snowflake-like. For the calculation of the electronic structure and scattering properties we employed the full-potential relativistic Korringa-Kohn-Rostoker Green-function method [D.S.G. Bauer, Schriften des Forschungszentrums Jülich, Key Tech. 79 (2014); N. H. Long et al., Phys. Rev. B 90, 064406 (2014)].
We enjoy close collaborations with P. Sessi and M. Bode (Würzburg University) and thank for financial support from the DFG (SPP-1666), the VITI project of the Helmholtz Association and computational support from the JARA-HPC Centre (RWTH Aachen University).