Possible superconductivity through the magnetic exchange in transition-metal intercalated bilayer graphene*

This study examines the possibility of superconductivity in transition-metal intercalated bilayer graphene. Using density functional theory, we determine electronic and magnetic properties through the electronic structure and density of states for all ten 3d transition-metal elements in a honeycomb configuration between two layers of graphene. Through an analysis of the electron density, we assess the induction of the magnetic moment in each case, where we estimate the exchange coupling through a comparison of the ferromagnetic and antiferromagnetic configurations. Furthermore, we show that the electronic band structure of the transition-metal intercalated layers have similar characteristics to those graphene layers intercalated with alkali and alkaline-earth metals, where superconductivity has been observed. Using a similar analysis, we find that the carbon π bands are below the Fermi, which is a possible indicator of superconductivity. More interestingly, the π bands seem to be degenerate to the transition-metal d bands, which could indicate hybridization and may lead to unconventional superconductivity.