Dresden 2020 – scientific programme
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O: Fachverband Oberflächenphysik
O 122: Topology and Symmetry Protected Materials II
O 122.7: Talk
Friday, March 20, 2020, 12:00–12:15, WIL A317
Probing non-trivial topology at Weyl nodes by dichroic photoemission — •Hendrik Bentmann1, Maximilian Ünzelmann1, Tim Figgemeier1, Philipp Eck2, Chul Hee Min3, Jeniffer Neu4, Theo Siegrist4, Domenico Di Sante2, Giorgio Sangiovanni2, and Friedrich Reinert1 — 1Experimentelle Physik VII and Würzburg-Dresden Cluster of Excellence ct.qmat, Universität Würzburg — 2Theoretische Physik I and and Würzburg-Dresden Cluster of Excellence ct.qmat, Universität Würzburg — 3Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel — 4National High Magnetic Field Laboratory, Tallahassee, USA
Weyl nodes are topologically protected intersections between non-degenerate bands and constitute the defining feature of Weyl semimetals. At these special points in momentum space the Bloch wave functions show a special behavior: in the bulk the Weyl nodes constitute monopoles of Berry flux and at the surface their projections define the termination points of Fermi-arc surface states. In this contribution we discuss how these effects can be addressed experimentally by use of dichroic angle-resolved photoemission spectroscopy (ARPES). In particular, we have studied the Weyl semimetal TaAs by VUV and soft X-ray ARPES to probe the surface and bulk electronic structure, respectively. Analyzing the linear and circular dichroism in comparison to first-principles calculations we observe direct indications of the topological behavior at the Weyl nodes [1]. [1] C. H. Min, HB, et al., Phys. Rev. Lett. 122, 116402 (2019).