title: Electronic structure of few-layer graphene: experimental demonstration of strong dependence on stacking sequence.
abstract: The electronic structure of few-layer graphene (FLG) samples with crystalline order was investigated experimentally by infrared absorption spectroscopy for photon energies ranging from 0.2-1 eV. Distinct optical conductivity spectra were observed for different samples having precisely the same number of layers. The different spectra arise from the existence of two stable polytypes of FLG, namely, Bernal (AB) stacking and rhombohedral (ABC) stacking. The observed absorption features, reflecting the underlying symmetry of the two polytypes and the nature of the associated van Hone singularities, were reproduced by explicit calculations within a tight-binding model. The findings demonstrate the pronounced effect of stacking order on the electronic structure of FLG.
authors.affiliation: Department of Physics, Columbia University, 538 West 120th Street, New York, New York 10027, USA.
authors.forename: Kin Fai
authors.initials: KF
authors.lastname: Mak
authors.forename: Jie
authors.initials: J
authors.lastname: Shan
authors.forename: Tony F
authors.initials: TF
authors.lastname: Heinz
mesh_terms: D000042:Absorption; D003460:Crystallization; D004583:Electrons; D006108:Graphite / Q000737:chemistry*; D008956:Models, Chemical; D015394:Molecular Structure; D049329:Nanostructures / Q000737:chemistry*; D017785:Photons; D013055:Spectrophotometry, Infrared
chemical_list: D006108:Graphite