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O: Fachverband Oberflächenphysik

O 88: Gerhard Ertl Young Investigator Award

O 88.3: Invited Talk

Thursday, March 15, 2018, 11:30–12:00, MA 005

Imaging spin polarization and orbital character at surfaces: from the Rashba effect to topological Fermi arcs — •H. Bentmann, H. Maass, C.-H. Min, and F. Reinert — Experimentelle Physik VII, Universität Würzburg

With the discovery of topological quantum states in solids, surface states have emerged from a niche phenomenon to a central concept in modern surface science and condensed matter physics, in general. Protected surface states with unconventional spin textures in momentum space are the hallmark of topological phases of matter being driven by spin-orbit interaction. Here, we shall present systematic spin- and angle-resolved photoemission investigations of strongly spin-orbit coupled surface states [1-3], spanning the range from the Rashba effect over topological insulators to the exotic Fermi arcs in Weyl semimetals. We will show that these experiments -based on a careful consideration of the photoemission transition-matrix-element [1]- are able to yield a detailed insight into the momentum-dependent structure of the surface-state wave function, in terms of spin polarization [1], orbital character [2], and bulk penetration [3]. For the example of the Weyl semimetal TaP, we will discuss how the measured orbital character across the Fermi surface reflects the non-trivial topology of the Fermi-arc surface states.

[1] HB et al., Phys. Rev. Lett. 119, 106401 (2017).

[2] H. Maass, HB, et al., Nature Commun. 7, 11621 (2016).

[3] C. Seibel, HB, et al., Phys. Rev. Lett. 114, 066802 (2015).