Research: CDW helps superconductiv­ity in CsV3Sb5

In recent years, the mutual interactions between nontrivial band topology, correlated electrons, and magnetism became of great interest. Layered kagome-lattice transition metal is emerging as an exciting platform owing to its peculiar band structure. Recent discovery of charge density wave (CDW) and superconductivity in a family of kagome metals AV₃Sb₅ (A = K, Rb, Cs) has sparked intense discussion about the origin of the intertwined correlated phases. In the present work, the researchers employed high-resolution ARPES technique to study the electronic properties of CDW and superconductivity in CsV₃Sb₅. The electronic instability via Fermi surface nesting is suggested to play a role in determining the CDW-related spectral features. The first-time observation of superconducting gap in AV₃Sb₅ by ARPES demonstrates the multiband superconductivity. The presence of finite density of states near E_F in the CDW phase is in favor of the superconductivity, especially the enhanced density of states associated with the CDW-induced flat band. The formation of CDW seems to prepare the seedbed for the multiband superconductivity at lower temperatures in CsV₃Sb₅.

R. Lou, A. Fedorov, Q. Yin, A. Kuibarov, Z. Tu, C. Gong, E. F. Schwier, B. Büchner, H. Lei, S. Borisenko,
Charge-Density-Wave-Induced Peak-Dip-Hump Structure and the Multiband Superconductivity in a Kagome Superconductor CsV₃Sb₅,
Phys. Rev. Lett. 128, 036402 (2022) (arXiv)