Unveiling Tunable Van Hove Singularity in Kagome Superconductors

Researchers have discovered that the energy level of the van Hove singularity (VHS) in the Ti-based kagome metal CsTi3Bi5 can be tuned without causing lattice structural instability. By introducing electrons through Cs surface doping, the VHS can be modulated in a wide energy range, generating electronic instabilities without affecting the structural stability. However, the electronic instability itself does not generate charge density waves in CsTi3Bi5. The study provides insights into the effects of electronic and lattice structural instabilities on charge density waves in kagome metals.