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arXiv · 2402.10031

Tomographic Imaging of Orbital Vortex Lines in Three-Dimensional Momentum Space

T. Figgemeier·M. Ünzelmann·P. Eck·J. Schusser·L. Crippa·J. N. Neu·B. Geldiyev·P. Kagerer·J. Buck·M. Kalläne·M. Hoesch·K. Rossnagel·T. Siegrist·L. -K. Lim·R. Moessner·G. Sangiovanni·D. Di Sante·F. Reinert·H. Bentmann
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Abstract

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

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T. Figgemeier, M. Ünzelmann, P. Eck, J. Schusser, L. Crippa, J. N. Neu, B. Geldiyev, P. Kagerer, J. Buck, M. Kalläne, M. Hoesch, K. Rossnagel, T. Siegrist, L. -K. Lim, R. Moessner, G. Sangiovanni, D. Di Sante, F. Reinert, H. Bentmann. 2024-02-15. Tomographic Imaging of Orbital Vortex Lines in Three-Dimensional Momentum Space. https://arxiv.org/abs/2402.10031

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