Carrier-induced lattice distortion (signature of strong electron-lattice interaction) in oxypnictide superconductors is found by a local structural study using extended X-ray absorption fine structure (EXAFS). Local lattice instability (polaron formation) is detected as an anomalous upturn of the mean-square relative displacement for the nearest neighbor distances (Fe-As) in LaFeAsO1-xFx (x = 0.07). Intimate correlation between local lattice mode and superconductivity is revealed. The results suggest that strong electron-lattice interaction is present as a common ingredient in the microscopic mechanism of superconducting transition.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Energy Engineering and Power Technology
- Electrical and Electronic Engineering