title: Graphite from the viewpoint of Landau level spectroscopy: an effective graphene bilayer and monolayer.
abstract: We describe an infrared transmission study of a thin layer of bulk graphite in magnetic fields up to B=34 T. Two series of absorption lines whose energy scales as sqrt[B] and B are present in the spectra and identified as contributions of massless holes at the H point and massive electrons in the vicinity of the K point, respectively. We find that the optical response of the K point electrons corresponds, over a wide range of energy and magnetic field, to a graphene bilayer with an effective interlayer coupling 2gamma_{1}, twice the value for a real graphene bilayer, which reflects the crystal ordering of bulk graphite along the c axis. The K point electrons thus behave as massive Dirac fermions with a mass enhanced twice in comparison to a true graphene bilayer.
authors.affiliation: Laboratoire National des Champs Magnétiques Intenses, CNRS, BP 166, F-38042 Grenoble Cedex 09, France. orlita@karlov.mff.cuni.cz
authors.forename: M
authors.initials: M
authors.lastname: Orlita
authors.forename: C
authors.initials: C
authors.lastname: Faugeras
authors.forename: J M
authors.initials: JM
authors.lastname: Schneider
authors.forename: G
authors.initials: G
authors.lastname: Martinez
authors.forename: D K
authors.initials: DK
authors.lastname: Maude
authors.forename: M
authors.initials: M
authors.lastname: Potemski