Electronic structure of graphene and related materials studied by ARPES

We report the fabrication and spectroscopy of graphene and its intercalation materials. We prepared single- and multi-layer graphene with or without a buffer layer on a SiC(0001) crystal by the hydrogen termination method. We also prepared Li -or Ca-intercalated bilayer graphene by the atom-replacement method. By using ARPES (angle-resolved photoemission spectroscopy), we studied the electronic structure of this novel graphene family. We observed a clear difference in the electronic structure between graphene with and without a buffer layer, which accounts for the reported difference in the transport properties between the two. In intercalated bi-layer graphene, we found an interlayer band below the Fermi level in the Ca case while it is absent in the Li one. This suggests a possible two-dimensional superconductivity in the thinnest limit of graphite intercalation compounds.