Assessing Nontrivial Topology in Weyl Semimetals by Dichroic Photoemission

The electronic structure of Weyl semimetals features Berry flux monopoles in the bulk and Fermi arcs at the surface. While angle-resolved photoelectron spectroscopy (ARPES) is successfully used to map the bulk and surface bands, it remains a challenge to explicitly resolve and pinpoint these topolog...

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Bibliographic Details
Published in:Physical review letters 2022-12, Vol.129 (24), p.246404-246404, Article 246404
Main Authors: Schusser, J, Bentmann, H, Ünzelmann, M, Figgemeier, T, Min, C-H, Moser, S, Neu, J N, Siegrist, T, Reinert, F
Format: Article
Language:English
Subjects:
angle-resolved photoemission spectroscopy
density functional theory
electronic structure
Fermi surface
Korringa-Kohn-Rostoker method
MATERIALS SCIENCE
surface states
topological materials
topology
Weyl semimetal
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Summary:The electronic structure of Weyl semimetals features Berry flux monopoles in the bulk and Fermi arcs at the surface. While angle-resolved photoelectron spectroscopy (ARPES) is successfully used to map the bulk and surface bands, it remains a challenge to explicitly resolve and pinpoint these topological features. Here we combine state-of-the-art photoemission theory and experiments over a wide range of excitation energies for the Weyl semimetals TaAs and TaP. Our results show that simple surface-band-counting schemes, proposed previously to identify nonzero Chern numbers, are ambiguous due to pronounced momentum-dependent spectral weight variations and the pronounced surface-bulk hybridization. Instead, our findings indicate that dichroic ARPES provides an improved approach to identify Fermi arcs but requires an accurate description of the photoelectron final state.
ISSN:0031-9007
1079-7114
DOI:10.1103/PhysRevLett.129.246404