Berlin 2015 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 88: Electronic Structure: Surface Magnetism and Spin Phenomena

O 88.5: Vortrag

Donnerstag, 19. März 2015, 16:00–16:15, MA 042

Spin Chirality in Momentum Space for Surface States on Tl/Si(111) and Tl/Ge(111) — •Sebastian D. Stolwijk¹, Philipp Eickholt¹, Kazuyuki Sakamoto², Anke B. Schmidt¹, Peter Krüger³, and Markus Donath¹ — ¹Physikalisches Institut, Westfälische Wilhelms-Universität Münster — ²Department of Nanomaterials Science, Chiba University, Japan — ³Institut für Festkörpertheorie, Westfälische Wilhelms-Universität Münster

The Tl/Si(111)-(1×1) surface is known for its spin-orbit-induced rotating spin pattern in momentum space along ΓK [1,2]. In this contribution, we focus on the unoccupied surface electronic structure around the M point of Tl/Si(111)-(1×1) and the isoelectronic surface Tl/Ge(111)-(1×1). On both surfaces, our spin- and angle-resolved inverse-photoemission experiments reveal a surface-derived state with giant spin-orbit-induced splitting, in agreement with our theoretical findings. While it lies within a band gap for Tl/Ge(111)-(1×1), it is degenerate with bulk bands on the Si substrate. In both cases, 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.
K. Sakamoto et al., Nature Commun. 4, 2073 (2013).
S.D. Stolwijk et al., Phys. Rev. Lett. 111, 176402 (2013).