| AVS 61st International Symposium & Exhibition | |
| Magnetic Interfaces and Nanostructures | Monday Sessions |
| Session MI-MoA |
| Session: | Topological Insulators/Rashba Effect |
| Presenter: | Henry Wortelen, Westfälische Wilhelms-Universität Münster, Germany |
| Authors: | H. Wortelen, Westfälische Wilhelms-Universität Münster, Germany H. Mirhosseini, Johannes Gutenberg-Universität, Germany J. Henk, Martin-Luther-Universität Halle-Wittenberg, Germany A.B. Schmidt, Westfälische Wilhelms-Universität Münster, Germany M. Donath, Westfälische Wilhelms-Universität Münster, Germany |
| Correspondent: | Click to Email |
The spin texture in the electronic structure of heavy elements and topological insulators, which is caused by spin-orbit interaction, is a hot topic of today´s research in condensed matter physics. On W(110), a spin-polarized Dirac-cone-like surface state has been found recently, which is reminiscent of topological surface states [1, 2]. While the occupied bands including this surface state are well investigated by spin- and angle-resolved photoemission, there is basically a blank area on the E(k||)-map above the Fermi level.
We present a combined experimental and theoretical study on the unoccupied electronic structure of W(110). We interpret our spin- and angle-resolved inverse photoemission experiments on the basis of band structure and one-step-model calculations. We compare results for Γ-N and Γ-H, which are nonequivalent due to the two-fold symmetry of the W(110) surface.
A complex spin structure is observed for the surface-state emissions, in which the symmetry of the respective states plays a crucial role. Using several photon detectors and therefore being sensitive to different photon takeoff angles result in different spin-polarization signals of the same electronic state even for normal electron incidence. This shows that the measured spin polarization is highly dependent on the geometry of the experimental setup and does not necessarily resemble the spin structure of the state under investigation. To derive the spin texture of the electronic states experimentally, the photon-emission process has to be taken into account. In this context, we will address how the symmetry of the states influences the observed spin polarization.
[1] K. Miyamoto et al., Phys. Rev. Lett. 108, 066808 (2012)
[2] H. Mirhosseini et al., New J. Phys. 15, 033019 (2013)