Search for electron-phonon coupling in superconducting BKBO

Ba0.6K0.4BiO3 is a superconductor with a Tc $=$ 30 K. While generally regarded as a BCS superconductor, previous work searching along the high-symmetry directions did not find characteristic signatures of electron-phonon coupling near the energy gap of $\sim$ 9 meV. Making use of the new Multizone Phonon Refinement technique, we are able to examine the phonon spectrum at all symmetry points and look for signatures of electron-phonon coupling.