Designing a path towards superconductivity through magnetic exchange in transition-metal intercalated bilayer graphene

Abstract

This study examines the potential of superconductivity in transition metal (TM) intercalated bilayer graphene through a systematic study of the electronic and magnetic properties. We determine the electronic structure for all first row TM elements in the stable honeycomb configuration between two layers of graphene using density functional theory (DFT). Through an analysis of the electron density, we assess the induction of the magnetic moment in each case, where a comparison of the ferromagnetic and antiferromagnetic configurations allow us to ascertain an estimated exchange coupling between the transition-metal elements. By analyzing the electronic properties, we find that the carbon $p$-bands are degenerate with the TM $d$-bands and form an electron pocket below the Fermi energy at the $\Gamma-$point. These hybridized bands are analogous to the carbon $p$-band effect that produces superconductivity in intercalated graphite with alkali and alkaline-earth metals. Furthermore, since the bands are hybridized with the TM $d$-bands, their magnetic properties may provide bosonic modes from their spin-coupling to preserve the unique linear dispersion present in monolayer graphene. This study provides a designing route by using TMs for tuning magneto-electric Dirac materials and will encourage future experimental studies to further the fundamental knowledge of unconventional superconductivity.