Anomalous Dirac charge dynamics in multilayer graphene at high optical transition energies

Almost all discussion of the optical absorption, the interlayer interaction and relationship between them in multilayer graphene is almost conclusively decided~ taking into account only the charge dynamic in states at K point in the hexagonal Brillouin zone while other states are relatively ignored. The lack of charge dynamic information at states beyond the Dirac cone may give us inadequate knowledge of their interaction with the lower states. Here, we present an optical conductivity study on graphene as function of layers using a combination of the dc-conductivity, optical ellipsometry, and vacuum ultraviolet (VUV) reflectance to reveal the electronic band structure and the novel interlayer interaction of graphene in pi and sigma bands over a broad energy range from 0 to 35 eV.