Electrons and phonons in YbC$_6$

Electronic structure and selected zone center phonons, as well as the electron-phonon coupling are calculated for a novel intercalated graphite supercoductor, YbC$_6$, using LDA+U method (fully localized version). The only stable solution either in LDA or in LDA+U is with zero spin and orbital polarization and the 4f band fully occupied. We show that Yb d states are present at the Fermi level and assess a hypothesis that superconductivity may arise from Yb phonons.