title: Role of valence changes and nanoscale atomic displacements in BiS2-based superconductors.
abstract: Superconductivity within layered crystal structures has attracted sustained interest among condensed matter community, primarily due to their exotic superconducting properties. EuBiS2F is a newly discovered member in the BiS2-based superconducting family, which shows superconductivity at 0.3 K without extrinsic doping. With 50 at.% Ce substitution for Eu, superconductivity is enhanced with Tc increased up to 2.2 K. However, the mechanisms for the Tcenhancement have not yet been elucidated. In this study, the Ce-doping effect on the self-electron-doped superconductor EuBiS2F was investigated by X-ray absorption spectroscopy (XAS). We have established a relationship between Ce-doping and the Tcenhancement in terms of Eu valence changes and nanoscale atomic displacements. The new finding sheds light on the interplay among superconductivity, charge and local structure in BiS2-based superconductors.
authors.affiliation: Center of Advanced Functional Ceramics, College of Science, Nanjing University of Posts and Telecommunications, Nanjing, Jiangsu 210023, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Cheng
authors.affiliation: Department of Physics, Zhejiang University, Hangzhou 310027, China.
authors.forename: Huifei
authors.initials: H
authors.lastname: Zhai
authors.affiliation: Shanghai Synchrotron Radiation Facility, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201204, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China.|Rome International Center for Materials Science, Superstripes, RICMASS, via dei Sabelli 119A, I-00185 Roma, Italy.
authors.forename: Wei
authors.initials: W
authors.lastname: Xu
authors.affiliation: Center of Advanced Functional Ceramics, College of Science, Nanjing University of Posts and Telecommunications, Nanjing, Jiangsu 210023, China.|Nanjing University (Suzhou) High-Tech Institute, Suzhou, 215123, China.
authors.forename: Shengli
authors.initials: S
authors.lastname: Liu
authors.affiliation: Department of Physics, Zhejiang University, Hangzhou 310027, China.
authors.forename: Guanghan
authors.initials: G
authors.lastname: Cao