Berlin 2024 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 55: Topology and Symmetry protected Materials (joint session O/TT)
O 55.10: Vortrag
Mittwoch, 20. März 2024, 17:15–17:30, HL 001
Orbital-momentum locking in chiral topological semimetal CoSi — •Stefanie Suzanne Brinkman1, Xin Liang Tan1,2, Øyvind Finnseth1, Anders Christian Mathisen1, Ying-Jiun Chen2, Christian Tusche2, and Hendrik Bentmann1 — 1Center for Quantum Spintronics, Department of Physics, NTNU, Norway — 2Forschungszentrum Jülich, Peter Grünberg Institut, Jülich, Germany
The chiral topological semimetal CoSi has a rich electronic structure in which unconventional chiral fermions and long surface Fermi arcs are observed near the Fermi level [1]. We studied the bulk electronic structure in CoSi using soft X-ray angle-resolved photoemission (ARPES) experiments via the ASPHERE endstation at PETRA III (DESY, Hamburg). We investigated the orbital character of the electronic states using circular dichroism in ARPES. Our results reveal the effect of the chiral crystal symmetry on the orbital structure in momentum space, and provide evidence of orbital-momentum locking as recently theoretically predicted [2]. This chirality-driven orbital texture with an accompanying large orbital Hall effect [2] paves the way towards applications of topological semimetals in spin- and orbitronics.
[1] Rao, Z. et al. Observation of unconventional chiral fermions with long Fermi arcs in CoSi. Nature 567, 496-499 (2019).
[2] Yang, Qun et al. Monopole-like orbital-momentum locking and the induced orbital transport in topological chiral semimetals. PNAS 120, 48 (2023).
Keywords: ARPES; electronic structure; chiral topological semimetals; dichroism; orbital-momentum locking