Highly Robust Reentrant Superconductivity in CsV<sub>3</sub>Sb<sub>5</sub> under Pressure
Xu Chen, Xinhui Zhan, Xiaojun Wang, Jun Deng, Xiao-Bing Liu, Xin Chen, Jian-Gang Guo, Xiaolong Chen
Abstract
We present the superconducting (SC) property and high-robustness of structural stability of kagome CsV 3 Sb 5 under in situ high pressures. For the initial SC-I phase, its T c is quickly enhanced from 3.5 K to 7.6 K and then totally suppressed at P ∼ 10 GPa. With further increasing pressure, an SC-II phase emerges at P ∼ 15 GPa and persists up to 100 GPa. The T c rapidly increases to the maximal value of 5.2 K at P = 53.6 GPa and slowly decreases to 4.7 K at P = 100 GPa. A two-dome-like variation of T c in CsV 3 Sb 5 is concluded here. The Raman measurements demonstrate that weakening of E 2g mode and strengthening of E 1g mode occur without phase transition in the SC-II phase, which is supported by the results of phonon spectra calculations. Electronic structure calculations reveal that exertion of pressure may bridge the gap of topological surface nontrivial states near E F , i.e., disappearance of Z 2 invariant. Meanwhile, the Fermi surface enlarges significantly, consistent with the increased carrier density. The findings here suggest that the change of electronic structure and strengthened electron-phonon coupling should be responsible for the pressure-induced reentrant SC.