Thickness-dependence of van Hove singularity in Li-intercalated graphene

Abstract

Unconventional superconductivity can be introduced in graphene by fine-tuning the van Hove singularity (VHS) position near the Fermi level. In this study, we examined the binding energy of VHS upon lithium intercalation into graphene with different thicknesses. From bilayer to multilayer, VHS shifted from the vicinity of the Fermi level to the occupied state by 60 meV. We performed first-principle calculations without and with the substrate. The former showed that interlayer interaction moves VHS more than experiments. The latter indicated that hybridization with the surface state of the substrate alters the dispersion of the Dirac bands, which can pin the VHS near the Fermi level.