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 Tc enhancement 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 Tc enhancement 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.
Highlights
Superconductivity within layered crystal structures has attracted sustained interest among condensed matter community, primarily due to their exotic superconducting properties
We investigated the local structure of EuBiS2F-based system as a function of Ce-doping by X-ray absorption spectroscopy (XAS), providing the atomic site-selective information of valence changes and nanoscale atomic displacements
For the Eu-containing superconductors, detailed investigations of the Eu valence change may provide valuable information on the electronic structure, which is fundamental for a better understanding of their superconductivity[22,23]
Summary
Superconductivity within layered crystal structures has attracted sustained interest among condensed matter community, primarily due to their exotic superconducting properties. Band structure calculations indicate that the undoped parent compounds such as LaBiS2O and SrBiS2F are insulators with an energy gap of 0.82 and 0.80 eV, respectively[11,12]. Upon electron doping, both compounds exhibit metallic conducting behavior and a superconducting transition at low temperatures[4,10]. How the Eu valence changes and its consequence on superconductivity in the parent and doped BiS2-based superconductors still remain unresolved. Similar to Fe-based superconductors, the interactions between superconducting BiS2 layers and blocking layers can be revealed via the nanoscale atomic displacements[17,18]. The X-ray absorption spectroscopy (XAS), consisting of the X-ray absorption near edge spectroscopy (XANES) and extended X-ray absorption fine structure (EXAFS) spectroscopy, is an ideal technique to retrieve
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call