Electron-phonon interaction and pairing mechanism in superconducting Ca-intercalated bilayer graphene

Using the ab initio anisotropic Eliashberg theory including Coulomb interactions, we investigate the electron-phonon interaction and the pairing mechanism in the recently-reported superconducting Ca-intercalated bilayer graphene. We find that C 6 CaC 6 can support phonon-mediated superconductivity with a critical temperature T c = 6.8–8.1 K, in good agreement with experimental data. Our calculations indicate that the low-energy Ca xy vibrations are critical to the pairing and that it should be possible to resolve two distinct superconducting gaps on the electron and hole Fermi surface pockets.