Topological surface states and flat bands in the kagome superconductor CsV3Sb5

Yong Hu; Samuel M L Teicher; Brenden R Ortiz; Yang Luo; Shuting Peng; Linwei Huai; Junzhang Ma; Nicholas C Plumb; Stephen D Wilson; Junfeng He; Ming Shi

doi:10.1016/j.scib.2021.11.026

Topological surface states and flat bands in the kagome superconductor CsV₃Sb₅

Sci Bull (Beijing). 2022 Mar 15;67(5):495-500. doi: 10.1016/j.scib.2021.11.026. Epub 2021 Nov 30.

Authors

Yong Hu¹, Samuel M L Teicher², Brenden R Ortiz², Yang Luo³, Shuting Peng³, Linwei Huai³, Junzhang Ma⁴, Nicholas C Plumb⁵, Stephen D Wilson⁶, Junfeng He⁷, Ming Shi⁸

Affiliations

¹ Department of Physics and CAS Key Laboratory of Strongly-coupled Quantum Matter Physics, University of Science and Technology of China, Hefei 230026, China; Swiss Light Source, Paul Scherrer Institute, Villigen PSI CH-5232, Switzerland.
² Materials Department and California Nanosystems Institute, University of California Santa Barbara, Santa Barbara, CA93106, USA.
³ Department of Physics and CAS Key Laboratory of Strongly-coupled Quantum Matter Physics, University of Science and Technology of China, Hefei 230026, China.
⁴ Department of Physics, City University of Hong Kong, Hong Kong, China.
⁵ Swiss Light Source, Paul Scherrer Institute, Villigen PSI CH-5232, Switzerland.
⁶ Materials Department and California Nanosystems Institute, University of California Santa Barbara, Santa Barbara, CA93106, USA. Electronic address: stephendwilson@ucsb.edu.
⁷ Department of Physics and CAS Key Laboratory of Strongly-coupled Quantum Matter Physics, University of Science and Technology of China, Hefei 230026, China. Electronic address: jfhe@ustc.edu.cn.
⁸ Swiss Light Source, Paul Scherrer Institute, Villigen PSI CH-5232, Switzerland. Electronic address: ming.shi@psi.ch.

PMID: 36546170
DOI: 10.1016/j.scib.2021.11.026

Abstract

Exotic quantum phenomena may appear in material systems with multiple orders or phases, where the mutual interactions can give rise to new physics beyond that of each component. Here, we report spectroscopic evidence for a unique combination of topology and correlation effects in the kagome superconductor CsV₃Sb₅. Topologically nontrivial surface states are observed near the Fermi energy (E_F), indicating that the topological physics may be active upon entering the superconducting state. Flat bands are observed, suggesting that electron correlation effects are also at play in this system. Our results reveal the peculiar electronic structure of CsV₃Sb₅, which holds the potential for realizing Majorana zero modes and anomalous superconducting states in kagome lattices. They also establish CsV₃Sb₅ as a unique platform for exploring the interactions between the charge order, topology, correlation effects and superconductivity.

Keywords: ARPES; Charge density wave order; Kagome superconductors; Topologically nontrivial surface states.