Grain boundaries in graphene on SiC(0001¯) substrate

Yann Tison (1) , J. Lagoute (1) , V. Repain (2) , C. Chacon (1) , Y. Girard (1) , F. Joucken , R. Sporken , F. Gargiulo (3) , O.V. Yazyev (4) , S. Rousset (5)

1 MPQ (UMR_7162) - Laboratoire Matériaux et Phénomènes Quantiques
2 GPS - Groupe de Physique des Solides
3 CAMS - Centre d'Analyse et de Mathématique sociales
4 EPFL- Institute of Theoretical Physics
5 UR ADBX - Aménités et dynamiques des espaces ruraux

Grain boundaries in epitaxial graphene on the SiC(0001¯) 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. © 2014 American Chemical Society.

Mots clés: Density functional theory; Graphene; Periodic structures; Silicon carbide; Buckling transitions; Misorientation angle; Ordered grain boundaries; Out of plane buckling; Periodic grain boundaries; Scanning tunneling microscopy and spectroscopy; Scanning tunneling spectroscopy; Small-angle grain boundaries; Grain boundaries; chemical structure; chemistry; scanning tunneling microscopy; surface property; Graphite; Microscopy; Scanning Tunneling; Models; Molecular; Silicon; Surface Properties

Domaines: Chimie

Yann Tison, J. Lagoute, V. Repain, C. Chacon, Y. Girard, et al.. Grain boundaries in graphene on SiC(0001¯) substrate. Nano Letters, 2014, 14 (11), pp.6382-6386. ⟨10.1021/nl502854w⟩. ⟨hal-01564395⟩