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O: Fachverband Oberflächenphysik
O 122: Topology and Symmetry Protected Materials II
O 122.4: Vortrag
Freitag, 20. März 2020, 11:15–11:30, WIL A317
Dichroic spin- and angle-resolved soft X-ray photoemission on a Weyl semimetal TaAs — •Maximilian Ünzelmann1, Tim Figgemeier1, Philipp Eck2, Matthias Kalläne3, Kai Rossnagel3,4, Domenico Di Sante2, Giorgio Sangiovanni2, Hendrik Bentmann1, and Friedrich Reinert1 — 1Experimentelle Physik 7, Universität Würzburg — 2Theoretische Physik 1, Universität Würzburg — 3Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel — 4Deutsches Elektronen-Synchrotron DESY
The interplay of inversion symmetry breaking (ISB) and spin-orbit coupling (SOC) lifts the spin degeneracy of electronic states in solids. In Weyl semimetals (WSM) structural ISB leads to spin-splittings in their bulk band structure, a key requirement for the formation of topologically protected Weyl points. Here we use angle-resolved soft x-ray photoemission to study the bulk electronic structure of the paradigmatic WSM TaAs. By means of spin-resolved measurements, we directly demonstrate the expected spin-splitting of the bulk bands. Moreover, circular dichroic measurements are in excellent agreement with the calculated momentum dependent orbital angular momentum (OAM). In contrast to spin angular momentum (SAM), OAM shows a parallel alignment in the spin-split states. This behavior is expected in materials where the characteristic energy scale of the ISB dominates over SOC [1,2].
[1] V. Sunko et al., Nature 549, 492 (2017), [2] J.-H. Park et al., Phys. Rev. B 85, 195401 (2012)