Berlin 2024 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

O: Fachverband Oberflächenphysik

O 95: Electronic Structure of Surfaces II: Spectroscopy, Surface States

O 95.2: Vortrag

Donnerstag, 21. März 2024, 15:15–15:30, MA 144

Dichroic Photoemission Tomography of Orbital Vortex Lines in a Topological Semimetal — •Maximilian Ünzelmann¹, Tim Figgemeier¹, Philipp Eck², Begmuhammet Geldiyev¹, Philipp Kagerer¹, Jakub Schusser¹, Domenico Di Sante³, Giorgio Sangiovanni², Friedrich Reinert¹, and Hendrik Bentmann⁴ — ¹Experimentelle Physik 7 and Würzburg-Dresden Cluster of Excellence ct.qmat, Universität Würzburg — ²ITPA Würzburg and Würzburg-Dresden Cluster of Excellence ct.qmat, Universität Würzburg — ³Department of Physics and Astronomy, Univerity of Bologna — ⁴Center for Quantum Spintronics, Department of Physics, NTNU, Norway

In this talk, we report on the discovery of orbital vortex lines (OVL) in the three-dimensional (3D) band structure of a topological semimetal. Using dichroic photoemission tomography, i.e., linear and circular dichroism applied at bulk-sensitive soft x-ray photon energies [1], we directly observe vortices of atomic orbital angular momentum (OAM) and trace their trajectories in full 3D momentum space. In the core of the OAM vortex we resolve a two-fold spin-degenerate Weyl nodal line [2]. The experimental data is supported by density functional theory as well as photoemission intensity calculations. Taken together, our experiments achieve the first imaging of non-trivial quantum-phase winding at line nodes.

[1] M. Ünzelmann et al., Nat. Commun., 12, 3650 (2021)

[2] M. Hirschmann et al. Phys. Rev. Mat., 5, 054202 (2021)

Keywords: Dichroism; ARPES; Topology; Nodal Line; Orbital Angular Momentum