Charge Density Wave Orders and Enhanced Superconductivity under Pressure in the Kagome Metal CsV Sb.

Superconductivity in topological kagome metals has recently received great research interests. Here, charge density wave (CDW) orders and the evolution of superconductivity under various pressures in CsV Sb single crystal with V kagome lattice are investigated. By using high-resolution scanning tunneling microscopy/spectroscopy (STM/STS), two CDW orders in CsV Sb are observed which correspond to 4a × 1a and 2a × 2a superlattices. By applying pressure, the superconducting transition temperature T is significantly enhanced and reaches a maximum value of 8.2 K at around 1 GPa. Accordingly, CDW state is gradually declined as increasing the pressure, which indicates the competing interplay between CDW and superconducting state in this material. The broad superconducting transitions around 0.4-0.8 GPa can be related to the strong competition relation among two CDW states and superconductivity. These results demonstrate that CsV Sb is a new platform for exploring the interplay between superconductivity and CDW in topological kagome metals.