title: Grain boundaries in graphene on SiC(0001̅) substrate.
abstract: Grain boundaries in epitaxial graphene on the SiC(0001̅) substrate are studied using scanning tunneling microscopy and spectroscopy. All investigated small-angle grain boundaries show pronounced out-of-plane buckling induced by the strain fields of constituent dislocations. The ensemble of observations determines the critical misorientation angle of buckling transition θc = 19 ± 2°. Periodic structures are found among the flat large-angle grain boundaries. In particular, the observed θ = 33 ± 2° highly ordered grain boundary is assigned to the previously proposed lowest formation energy structural motif composed of a continuous chain of edge-sharing alternating pentagons and heptagons. This periodic grain boundary defect is predicted to exhibit strong valley filtering of charge carriers thus promising the practical realization of all-electric valleytronic devices.
authors.affiliation: Laboratoire Matériaux et Phénomènes Quantiques, Universié Paris Diderot-Paris 7, Sorbonne Paris Cité, CNRS, UMR 7162 , 10 rue A. Domon et L. Duquet, 75205 Paris 13, France.
authors.forename: Yann
authors.initials: Y
authors.lastname: Tison
authors.forename: Jérôme
authors.initials: J
authors.lastname: Lagoute
authors.forename: Vincent
authors.initials: V
authors.lastname: Repain
authors.forename: Cyril
authors.initials: C
authors.lastname: Chacon
authors.forename: Yann
authors.initials: Y
authors.lastname: Girard
authors.forename: Frédéric
authors.initials: F
authors.lastname: Joucken
authors.forename: Robert
authors.initials: R
authors.lastname: Sporken
authors.forename: Fernando
authors.initials: F
authors.lastname: Gargiulo
authors.forename: Oleg V
authors.initials: OV
authors.lastname: Yazyev
authors.forename: Sylvie
authors.initials: S
authors.lastname: Rousset
mesh_terms: D006108:Graphite / Q000737:chemistry*; D016252:Microscopy, Scanning Tunneling; D008958:Models, Molecular; D012825:Silicon / Q000737:chemistry; D013499:Surface Properties
chemical_list: D006108:Graphite; D012825:Silicon
keywords: Graphene; density functional theory; grain boundaries; scanning tunneling microscopy; scanning tunneling spectroscopy