Highly Robust Reentrant Superconductivity in CsV3Sb5 under PressureSupported by the National Key Research and Development Program of China (Grant Nos. 2017YFA0304700, 2018YFE0202601, and 2016YFA0300600), the National Natural Science Foundation of China (Grant Nos. 51922105, 11804184, 11974208, and 51772322), the Chinese Academy of Sciences (Grant No. QYZDJ-SSW-SLH013), the Beijing Natural Science Foundation (Grant No. Z200005), and the Shandong Provincial Natural Science

Abstract

We present the superconducting (SC) property and high-robustness of structural stability of kagome CsV3Sb5 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 CsV3Sb5 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.