Berlin 2018 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 68: Topological Insulators and Weyl Semimetals (joint session MA/TT)
TT 68.6: Vortrag
Mittwoch, 14. März 2018, 16:15–16:30, EB 407
Circular-polarized-light induced spin characterization of Dirac-cone surface state at W(110) — •Koji Miyamoto1, Henry Wortelen2, Taichi Okuda1, Jürgen Henk3, and Markus Donath2 — 1HSRC, Japan — 2WWU Münster, Germany — 3MLU, Germany
Recently, for the topological surface state (TSS) of Bi2Se3, several groups have observed an interesting phenomenon by spin- and angle-resolved photoemission (SARPE): the observed spin features of the photoelectrons are strongly dependent on the light polarization [1]. This effect is currently highly debated in the field of optospintronics. So far, the observations of the effect are limited to surfaces with C3v symmetry.
The surface of W(110) shows a spin-polarized Dirac-cone-like state within a spin-orbit-induced gap, which is reminiscent of a TSS [2]. Here, in contrast to so-far studied topological insulators, the surface structure has C2v symmetry.
We studied spin feature of the Dirac-cone-like surface state along Γ H at W(110) by using SARPE with left and right circular polarized light. It is found that the observed spin textures is caused by spin dependent matrix element influenced by C2v symmetry. This finding opens a new way to manipulate the spin polarization of photoelectron in systems with C2v symmetry.
*[1] C. Jozwiak et al., Nat., Phys. 9, 293 (2013).
*[2] K. Miyamoto et al., Phys. Rev. Lett. 108, 066808 (2012).