The competition between charge density wave and superconductivity in the kagome metal CsV3(Sb1-xPbx)5 single crystals

Abstract

Kagome metal AV3Sb5 (A = K, Rb, Cs) has garnered considerable attention for its abundant exotic quantum phenomena and the special competitive relationship between charge density wave (CDW) and superconductivity (SC). In this work we explore the unconventional coupling between charge density wave and superconductivity by means of the substitutional doping of Pb atoms with Sb atoms. Microscopic characterization and performance tests provide valuable phase diagram information for CsV3(Sb1-xPbx)5. Upon Pb doping, a pronounced competition between the charge density wave transition temperature TCDW and the superconducting temperature Tc was observed. Analysis of changes in Debye temperature ΘD and lattice constant, it is shown that Pb doping affects atomic bonding and may strengthen the coupling between adjacent kagome layers to some extent. Furthermore, the small angular shift of the diffraction peak and increased full width at half maximum (FWHM) indicate that the doping causes crystal defects and distorts the crystal structure, which will change the charge density in the local area and may affect the superconductivity. This result further reveals a close correlation between the superconductivity of the system and the electronic structure of the kagome plane in the CsV3Sb5 system. Overall, our results suggest that the observed competition arises from the complex interplay of multiple factors.