Topological surface states and flat bands in the kagome superconductor CsV3Sb5

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. (c) 2021 Science China Press. Published by Elsevier B.V. and Science China Press. All rights reserved.

Automated summary

This study reports the spectroscopic evidence of topology and correlation effects in the kagome superconductor CsV3Sb5. The presence of topologically nontrivial surface states and flat bands suggests the potential for realizing Majorana zero modes and anomalous superconducting states in kagome lattices. CsV3Sb5 is established as a unique platform for exploring the interactions between charge order, topology, correlation effects, and superconductivity.