title: Formation of unconventional standing waves at graphene edges by valley mixing and pseudospin rotation.
abstract: We investigate the roles of the pseudospin and the valley degeneracy in electron scattering at graphene edges. It is found that they are strongly correlated with charge density modulations of short-wavelength oscillations and slowly decaying beat patterns in the electronic density profile. Theoretical analyses using nearest-neighbor tight-binding methods and first-principles density-functional theory calculations agree well with our experimental data from scanning tunneling microscopy. The armchair edge shows almost perfect intervalley scattering with pseudospin invariance regardless of the presence of the hydrogen atom at the edge, whereas the zigzag edge only allows for intravalley scattering with the change in the pseudospin orientation. The effect of structural defects at the graphene edges is also discussed.
authors: Department of Physics and Astronomy, Seoul National University, Seoul 151-747, Korea.
authors: Changwon
authors: C
authors: Park
authors: Heejun
authors: H
authors: Yang
authors: Andrew J
authors: AJ
authors: Mayne
authors: Gérald
authors: G
authors: Dujardin
authors: Sunae
authors: S
authors: Seo
authors: Young
authors: Y
authors: Kuk
authors: Jisoon
authors: J
authors: Ihm
authors: Gunn
authors: G
authors: Kim
mesh_terms: D002621:Chemistry / Q000379:methods; D003460:Crystallization; D004563:Electrochemistry / Q000379:methods; D004581:Electronics; D006108:Graphite / Q000737:chemistry*; D006859:Hydrogen / Q000737:chemistry; D007477:Ions; D007700:Kinetics; D008956:Models, Chemical; D008962:Models, Theoretical; D009991:Oscillometry / Q000379:methods; D012542:Scattering, Radiation
chemical_list: D007477:Ions; D006108:Graphite; D006859:Hydrogen