Dresden 2017 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 51: Topological Insulators (joint session DS, HL, MA, O, TT, organized by MA)
TT 51.4: Talk
Wednesday, March 22, 2017, 15:45–16:00, HSZ 401
Spin-dependent very-low-energy electron diffraction at Bi2Se3 — •Andre Reimann1, Christian Langenkämper1, Anna Blob1, Jürgen Braun2, and Markus Donath1 — 1Physikalisches Institut, Westfälische Wilhelms-Universität Münster, Germany — 2Department Chemie, Ludwig-Maximilians-Universität München, Germany
The topological insulator Bi2Se3 exhibits prominent spin effects in both the occupied and unoccupied electronic bandstructure due to strong spin-orbit coupling. This promises large effects also for spin-dependent electron reflection.
We present a combined experimental and theoretical study of the spin-dependent electron reflection of Bi2Se3 along the Γ K and the Γ M direction. Experimentally we performed spin-dependent very-low-energy electron diffraction (VLEED) experiments over a wide range of energies and angles of incidence. Theoretically we used ab-initio calculations by means of the SPKKR layer code.
For both directions, we derived maps for the reflectivity and the Sherman function. We found high spin asymmetries up to 37%, which are caused by the large spin-orbit coupling of Bi2Se3. These features show a strong energy and angle dependence. Futhermore, we identified the VLEED finestructures, which contain information about the surface barrier.