Regensburg 2016 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 38: Spintronics
O 38.8: Vortrag
Dienstag, 8. März 2016, 15:45–16:00, S051
Energy Dispersion and Spin Structure of Unoccupied States of BiTeI: A Matter of Surface Termination? — •Christian Langenkämper1, Koji Miyamoto1, Anke B. Schmidt1, Peter Krüger2, and Markus Donath1 — 1Physikalisches Institut, Westfälische Wilhelms-Universität Münster, Germany — 2Institut für Festkörpertheorie, Westfälische Wilhelms-Universität Münster, Germany
We present a combined experimental and theoretical study on the unoccupied electronic structure of BiTeI along the Γ-K direction. We performed spin-resolved inverse-photoemission experiments on samples with different surface termination, Te and I.
For the two surface terminations we found distinct differences in the energy dispersion of the surface states around Γ, which are caused by band bending. In contrast, this effect is not observed around the K point. With the help of ab initio band-structure calculations we identify the observed states as bulk states, not influenced by band bending.
In addition, we studied the spin structure of the unoccupied bands. Around the Γ point, we found a Rashba-type in-plane spin polarization. Upon approaching K, the direction of the spin polarization rotates from fully in-plane to out-of-plane. This spin texture is in accordance with the crystal symmetry and independent of the surface termination.