Charge-Density-Wave-Induced Bands Renormalization and Energy Gaps in a Kagome Superconductor RbV3Sb5

Recently discovered Z(2) topological kagome metals AV(3)Sb(5) (A = K, Rb, and Cs) exhibit charge-densitywave (CDW) phases and novel superconducting paring states providing a versatile platform for studying the interplay between electron correlation and quantum orders. Here we directly visualize CDW-induced bands renormalization and energy gaps in RbV3Sb5 using angle-resolved photoemission spectroscopy pointing to the key role of tuning van Hove singularities to the Fermi energy in mechanisms of ordering phases. Near the CDW transition temperature, the bands around the Brillouin zone (BZ) boundary are shifted to high-binding energy, forming an M-shaped band with singularities near the Fermi energy. The Fermi surfaces are partially gapped, and the electronic states on the residual ones should be possibly dedicated to the superconductivity. Our findings are significant in understanding CDW formation and its associated superconductivity.

Automated summary

The newly discovered Z(2) topological kagome metals AV(3)Sb(5) exhibit CDW phases and novel superconducting pairing states, with a focus on the key role of tuning van Hove singularities to the Fermi energy in ordering mechanisms. The bands around the Brillouin zone boundary in RbV3Sb5 shift to high-binding energy near the CDW transition temperature, forming an M-shaped band with singularities near the Fermi energy. The partially gapped Fermi surfaces and electronic states on residual bands may play a role in superconductivity.