Superconductivity in graphene-lithium

We present first-principles calculations on systems consisting of a few layers of graphene and lithium. In particular, we investigate the evolution of the electron–phonon coupling strength with increasing number of layers. We find that, for intercalated systems such as C₆-Li-C₆ or C₆-Li-C₆-Li-C₆, the electron–phonon coupling is weak. However, for systems of equal number of graphene and lithium layers, such as C₆-Li or C₆-Li-C₆-Li, the electron–phonon coupling is strong. We investigate the optimal configuration that yields the highest superconducting transition temperature. (letter)