Rich nature of Van Hove singularities in Kagome superconductor CsV₃Sb₅
Creators
- 1. Photon Science Division, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
- 2. Max-Planck-Institut für Festkörperforschung, Heisenbergstrasse 1, D-70569 Stuttgart, Germany
- 3. CAS Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, 100190 Beijing, China
- 4. Materials Department and California Nanosystems Institute, University of California Santa Barbara, Santa Barbara, CA 93106, USA
- 5. Department of Physics and Center of Theoretical and Computational Physics, University of Hong Kong, Hong Kong, China
- 6. Kavli Institute of Theoretical Sciences, University of Chinese Academy of Sciences, 100049 Beijing, China
- 7. Department of Physics, City University of Hong Kong, Kowloon, Hong Kong, China
- 8. City University of Hong Kong Shenzhen Research Institute, Shenzhen, China
- 9. Hong Kong Institute for Advanced Study, City University of Hong Kong, Kowloon, Hong Kong, China
- 10. Institute for Theoretical Physics, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany
- 11. Department of Physics and Quantum Centers in Diamond and Emerging Materials (QuCenDiEM) group, Indian Institute of Technology Madras, Chennai 600036, India
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Description
The recently discovered layered kagome metals AV₃Sb₅ (A=K, Rb, Cs) exhibit diverse correlated phenomena, which are intertwined with a topological electronic structure with multiple van Hove singularities (VHSs) in the vicinity of the Fermi level. As the VHSs with their large density of states enhance correlation effects, it is of crucial importance to determine their nature and properties. Here, we combine polarization-dependent angle- resolved photoemission spectroscopy with density functional theory to directly reveal the sublattice properties of 3d-orbital VHSs in CsV₃Sb₅. Four VHSs are identified around the M point and three of them are close to the Fermi level, with two having sublattice-pure and one sublattice-mixed nature. Remarkably, the VHS just below the Fermi level displays an extre- mely flat dispersion along MK, establishing the experimental discovery of higher-order VHS. The characteristic intensity modulation of Dirac cones around K further demonstrates the sublattice interference embedded in the kagome Fermiology. The crucial insights into the electronic structure, revealed by our work, provide a solid starting point for the understanding of the intriguing correlation phenomena in the kagome metals AV₃Sb₅.
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References
Journal reference Hu, Y., Wu, X., Ortiz, B.R. et al. Rich nature of Van Hove singularities in Kagome superconductor CsV3Sb5. Nat Commun 13, 2220 (2022)., doi: 10.1038/s41467-022-29828-x