A Raman study of superconducting crystals of Ba1−xKxBiO3

Abstract To discuss the nature of superconductivity in the cubic Ba 1− x K x BiO 3 it is important to understand the role of phonons and their interaction with conduction electrons in both insulating and superconducting phases. In order to provide information on the electron-phonon coupling we performed Raman experiments as a function of temperature in single crystalline samples. The high quality of the spectra allowed us to fit most lines to either Lorentzian or Fano lineshapes and study the dependence of the parameters as function of temperature.