We present the superconducting(SC) property and high-robustness of structural stability of kagome CsV_3Sb_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 t...We present the superconducting(SC) property and high-robustness of structural stability of kagome CsV_3Sb_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_3Sb_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 Z2 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.展开更多
基金Supported by the National Key Research and Development Program of China (Grant Nos.2017YFA0304700,2018YFE0202601,and2016YFA0300600)the National Natural Science Foundation of China (Grant Nos.51922105,11804184,11974208,and 51772322)+2 种基金the Chinese Academy of Sciences (Grant No.QYZDJ-SSW-SLH013)the Beijing Natural Science Foundation (Grant No.Z200005)the Shandong Provincial Natural Science Foundation (Grant Nos.ZR2020YQ05,ZR2019MA054,and 2019KJJ020)。
文摘We present the superconducting(SC) property and high-robustness of structural stability of kagome CsV_3Sb_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_3Sb_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 Z2 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.
