Distinct pressure evolution of superconductivity and charge-density-wave in kagome superconductor CsV${}_3$Sb${}_5$ thin flakes

Abstract

It is intriguing to explore the coexistence and (or) competition between charge-density-wave (CDW) and superconductivity (SC) in many correlated electron systems, such as cuprates, organic superconductors and dichacolgenides. Among them, the recently discovered ${\mathbb{Z}}_2$ topological kagome metals AV${}_3$Sb${}_5$ (A=K, Rb, Cs) serve as an ideal platform to study the intricate relation between them. Here, we report the electrical resistance measurements on CsV${}_3$Sb${}_5$ thin flakes ($\approx$ 60 nm) under hydrostatic pressure up to 2.12 GPa to compare its pressure phase diagram of CDW and SC with its bulk form. Even though the CDW transition temperature (T${}_{CDW}$) in CsV${}_3$Sb${}_5$ thin flakes is still monotonically suppressed under pressure and totally vanishes at P${}_2$=1.83 GPa similar to the bulk, the superconducting transition temperature (T${}_c$) shows an initial decrease and consequent increase up to its maximum $\sim$ 8.03 K at P${}_2$, in sharp contrast with the M-shaped double domes in the bulk CsV${}_3$Sb${}_5$. Our results suggest the important role of reduced dimensionality on the CDW state and its interplay with the SC, offering a new perspective to explore the exotic nature of CsV${}_3$Sb${}_5$.

7 pages, 5 figures