Magnetoreflection study of graphite intercalated with bromine

We report here the first observation of interband Landau level transitions in graphite intercalation compounds. Magnetoreflection measurements are reported for residue compounds of graphite intercalated with up to 1.2 at.% Br. The observed magnetoreflection resonances show evidence for domains in which the electronic band structure and Fermi energy are only slightly dependent on bromine concentration. These conclusions are in general agreement with recently reported de Haas-van Alphen results for these compounds.