Theoretical Investigation of Two-Dimensional Superconductivity in Intercalated Graphene Layers

First-principles calculations of the electronic structure and vibrational modes, in a system of graphene bilayers and trilayers intercalated with alkaline earth atoms, are resented. It is found that, in similarity to the case of superconducting graphite intercalation compounds, the Fermi level is crossed by an s-band derived from the intercalant states, as well as graphitic pi-bands. The electron-phonon coupling parameter is found to be 0.60 and 0.80, respectively, in calcium intercalated graphene bilayers and trilayers. In superconducting CaC6 graphite intercalation compound, the calculated value for the electron-phonon coupling parameter is 0.83. It is concluded that two-dimensional superconductivity is possible in a system of a few graphene layers intercalated with calcium.