Regensburg 2016 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 48: Electronic Structure: Surface Magnetism and Spin Phenomena

O 48.4: Poster

Dienstag, 8. März 2016, 18:15–20:30, Poster E

W(110) and Ta(110): A Playground for Spin-Orbit-Induced Effects on Surface States — •H. Wortelen¹, K. Miyamoto², H. Mirhosseini³, B. Engelkamp¹, A.B. Schmidt¹, J. Henk⁴, and M. Donath¹ — ¹Universität Münster — ²HSRC, Hiroshima University — ³MPI für Mikrostrukturphysik Halle — ⁴Universität Halle-Wittenberg

The influence of spin-orbit effects on the surface electronic structure of W(110) and Ta(110) was investigated with spin- and angle-resolved photoemission and inverse photoemission experiments and electronic-structure calculations. We present a comprehensive E(k_∥) picture of the electronic states and their spin texture in the occupied and unoccupied regime.

Tungsten and tantalum, direct neighbors in the periodic table, exhibit a very similar electronic structure, yet with a shifted Fermi energy due to the one electron difference. Both elements exhibit a bcc crystal structure, however, with different lattice parameters resulting in differently pronounced hybridization of surface and bulk bands. As a consequence, a Dirac-cone-like surface state, reminiscent of a topological surface state, observed for W(110) below E_F [1,2] has no apparent equivalent on Ta(110), although it is expected above E_F [3]. Furthermore, a Rashba-split d_z² surface state appears on Ta(110) [4], which has no equivalent on W(110).

[1] Miyamoto et al., Phys. Rev. Lett. 108, 066808 (2012)

[2] Mirhosseini et al., New J. Phys. 15, 033019 (2013)

[3] Engelkamp et al., Phys. Rev. B 92, 085401 (2015)

[4] Wortelen et al., Phys. Rev. B 92, 161408(R) (2015)