Momentum-space signatures of Berry flux monopoles in the Weyl semimetal TaAs
Please always quote using this URN: urn:nbn:de:bvb:20-opus-260719
- Since the early days of Dirac flux quantization, magnetic monopoles have been sought after as a potential corollary of quantized electric charge. As opposed to magnetic monopoles embedded into the theory of electromagnetism, Weyl semimetals (WSM) exhibit Berry flux monopoles in reciprocal parameter space. As a function of crystal momentum, such monopoles locate at the crossing point of spin-polarized bands forming the Weyl cone. Here, we report momentum-resolved spectroscopic signatures of Berry flux monopoles in TaAs as a paradigmatic WSM. WeSince the early days of Dirac flux quantization, magnetic monopoles have been sought after as a potential corollary of quantized electric charge. As opposed to magnetic monopoles embedded into the theory of electromagnetism, Weyl semimetals (WSM) exhibit Berry flux monopoles in reciprocal parameter space. As a function of crystal momentum, such monopoles locate at the crossing point of spin-polarized bands forming the Weyl cone. Here, we report momentum-resolved spectroscopic signatures of Berry flux monopoles in TaAs as a paradigmatic WSM. We carried out angle-resolved photoelectron spectroscopy at bulk-sensitive soft X-ray energies (SX-ARPES) combined with photoelectron spin detection and circular dichroism. The experiments reveal large spin- and orbital-angular-momentum (SAM and OAM) polarizations of the Weyl-fermion states, resulting from the broken crystalline inversion symmetry in TaAs. Supported by first-principles calculations, our measurements image signatures of a topologically non-trivial winding of the OAM at the Weyl nodes and unveil a chirality-dependent SAM of the Weyl bands. Our results provide directly bulk-sensitive spectroscopic support for the non-trivial band topology in the WSM TaAs, promising to have profound implications for the study of quantum-geometric effects in solids. Weyl semimetals exhibit Berry flux monopoles in momentum-space, but direct experimental evidence has remained elusive. Here, the authors reveal topologically non-trivial winding of the orbital-angular-momentum at the Weyl nodes and a chirality-dependent spin-angular-momentum of the Weyl bands, as a direct signature of the Berry flux monopoles in TaAs.…
Author: | M. Ünzelmann, H. Bentmann, T. Figgemeier, P. Eck, J. N. Neu, B. Geldiyev, F. Diekmann, S. Rohlf, J. Buck, M. Hoesch, M. Kalläne, K. Rossnagel, R. Thomale, T. Siegrist, G. Sangiovanni, D. Di Sante, F. Reinert |
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URN: | urn:nbn:de:bvb:20-opus-260719 |
Document Type: | Journal article |
Faculties: | Fakultät für Physik und Astronomie / Physikalisches Institut |
Language: | English |
Parent Title (English): | Nature Communications |
Year of Completion: | 2021 |
Volume: | 12 |
Issue: | 1 |
Article Number: | 3650 |
Source: | Nature Communications (2021) 12:1, 3650. https://doi.org/10.1038/s41467-021-23727-3 |
DOI: | https://doi.org/10.1038/s41467-021-23727-3 |
Dewey Decimal Classification: | 5 Naturwissenschaften und Mathematik / 53 Physik / 530 Physik |
Tag: | electronic properties and materials; topological insulators |
Release Date: | 2022/03/31 |
EU-Project number / Contract (GA) number: | 897276 |
OpenAIRE: | OpenAIRE |
Open-Access-Publikationsfonds / Förderzeitraum 2021 | |
Licence (German): | CC BY: Creative-Commons-Lizenz: Namensnennung 4.0 International |