Band Structure of K(2x2) on graphene

The electronic structure of K(2x2) on graphene, the same stochiometry as bulk KC$_{8}$, was studied using angle-resolved photoemission spectroscopy (ARPES). In addition to bands derived from the graphene $\pi $ states an intercalant induced ``interlayer band'' is observed centered at $\Gamma $. Of these two bands, the dominant mass renormalization occurs in the $\pi $-derived bands, as determined by characterization of the ``kinks'' in the dispersion measured by ARPES. This suggests that the superconductivity in bulk KC$_{8}$ has a more important role than the interlayer band.