| AVS 61st International Symposium & Exhibition | |
| Magnetic Interfaces and Nanostructures | Monday Sessions |
| Session MI-MoA |
| Session: | Topological Insulators/Rashba Effect |
| Presenter: | Markus Donath, Muenster University, Germany |
| Authors: | M. Donath, Muenster University, Germany S.D. Stolwijk, Muenster University, Germany P. Eickholt, Muenster University, Germany A.B. Schmidt, Muenster University, Germany K. Sakamoto, Chiba University, Japan P. Krueger, Muenster University, Germany |
| Correspondent: | Click to Email |
The Tl/Si(111)-(1x1) surface is known for its outstanding properties due to spin-orbit interaction: a rotating spin pattern in momentum space and an unoccupied surface state with giant spin splitting at the K point [1,2]. In this contribution, we focus on the unoccupied surface electronic structure along the ΓM and MK high-symmetry directions. Spin- and angle-resolved inverse-photoemission experiments with sensitivity to the in-plane and the out-of-plane components of the spin-polarization vector were performed with our recently developed rotatable spin-polarized electron source [3]. Along both high-symmetry directions, our experiments reveal a surface-derived state with giant spin-orbit-induced splitting, in agreement with our theoretical findings. The state is purely in-plane polarized along ΓM, whereas the out-of-plane component is dominant along KM. As a consequence, spin chirality is found in momentum space around the M point.
We will compare our results for Tl/Si(111) with data for the isoelectronic Tl/Ge(111) surface. Differences in the surface electronic structure between the two surfaces appear along ΓM, where the Rashba-type spin-split surface state on Tl/Ge(111) lies within a band gap, while it is degenerate with bulk bands on the Si substrate. Consequences for the spin texture will be discussed.
[1] K. Sakamoto et al., Nature Commun. 4, 2073 (2013).
[2] S.D. Stolwijk et al., Phys. Rev. Lett. 111, 176402 (2013).
[3] S.D. Stolwijk et al., Rev. Sci. Instrum. 85, 013306 (2014).