%0 Electronic Article
%A Figgemeier, T.
%A Ünzelmann, M.
%A Eck, P.
%A Schusser, J.
%A Crippa, L.
%A Neu, J. N.
%A Geldiyev, B.
%A Kagerer, P.
%A Buck, J.
%A Kalläne, M.
%A Hoesch, M.
%A Rossnagel, K.
%A Siegrist, T.
%A Lim, L. -K.
%A Moessner, R.
%A Sangiovanni, G.
%A Di Sante, D.
%A Reinert, F.
%A Bentmann, H.
%T Tomographic Imaging of Orbital Vortex Lines in Three-Dimensional Momentum Space
%N arXiv:2402.10031
%M PUBDB-2025-00813
%M arXiv:2402.10031
%D 2024
%X We report the experimental discovery of orbital vortex lines in the three-dimensional (3D) band structure of a topological semimetal. Combining linear and circular dichroism in soft x-ray angle-resolved photoemission (SX-ARPES) with first-principles theory, we image the winding of atomic orbital angular momentum, thereby revealing - and determining the location of - lines of vorticity in full 3D momentum space. Our observation of momentum-space vortex lines with quantized winding number establishes an analogue to real-space quantum vortices, for instance, in type-II superconductors and certain non-collinear magnets. These results establish multimodal dichroism in SX-ARPES as an approach to trace 3D orbital textures. Our present findings particularly constitute the first imaging of non-trivial quantum-phase winding at line nodes and may pave the way to new orbitronic phenomena in quantum materials
%F PUB:(DE-HGF)25
%9 Preprint
%U https://bib-pubdb1.desy.de/record/624344