EXAFS study in organic superconductors

Abstract Cu K-edge extended X-ray absorption fine structure (EXAFS) measurements have been made in the organic superconductors, ϰ-(BEDT-TTF) 2 Cu(NCS) 2 and ϰ-(BEDT-TTF) 2 Cu[N(CN) 2 ]Br from 300 K down to 20 K. Some anomalies of the local structure were found from the temperature dependence of EXAFS signal, in particular nearest neighbors distance (R). The anomalies can be ascribed to the hydrogen bonds between cations and anions.