Electron pairing by remote-phonon scattering in oxide-supported graphene

Using first principles calculations (density functional theory) we find that placing graphene on an (111)-oriented perovskite SrTiO₃ (STO) surface provides a convenient doping mechanism. Moreover, further theoretical analysis suggests that coupling of electrons in graphene to interfacial hybrid plasmon/optical modes via remote-phonon scattering may result in an effective attractive electron-electron interaction that, in turn, could lead to electron pairing and superconductivity. Specifically, we consider the graphene sheet supported by the STO and also gated. Using the full RPA dynamic polarizability of the whole system (including the hybrid mode arising from the coupling of the graphene plasmons to the optical phonons of the STO substrate and gate insulator), we estimate the superconductive transition temperature in both the weak- and the (Eliashberg) strong-coupling limits and also by solving the gap equation.