Carrier Injection and Manipulation of Charge-Density Wave in Kagome Superconductor CsV3Sb5

Kagome metals AV3Sb5 (A = K, Rb, and Cs) exhibit a unique superconducting ground state coexisting with charge-density wave (CDW), whereas how these characteristics are affected by carrier doping remains unexplored because of the lack of an efficient carrier-doping method. Here we report successful electron doping to CsV3Sb5 by Cs dosing, as visualized by angle-resolved photoemission spectroscopy. We found that the electron doping with Cs dosing proceeds in an orbital-selective way, as characterized by a marked increase in electron filling of the Sb 5pz and V 3dxz/yz bands as opposed to relatively insensitive nature of the V 3dxy/x2-y2 bands. By monitoring the temperature evolution of the CDW gap around the M point, we found that the CDW can be completely killed by Cs dosing while keeping the saddle point with the V 3dxy/x2-y2 character almost pinned at the Fermi level. The present result suggests a crucial role of multi-orbital effect to the occurrence of CDW, and provides an important step toward manipulating the CDW and superconductivity in AV3Sb5.
Comment: 7 pages, 3 figures