Grain boundaries in graphene on SiC(0001¯) substrate

Yann Tison, Jérôme Lagoute, Vincent Repain, Cyril Chacon, Yann Girard, Frédéric Joucken, Robert Sporken, Fernando Gargiulo, Oleg V. Yazyev, Sylvie Rousset

    Research output: Contribution to journalArticlepeer-review

    Abstract

    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.

    Original languageEnglish
    Pages (from-to)6382-6386
    Number of pages5
    JournalNano Letters
    Volume14
    Issue number11
    Early online date20 Oct 2014
    DOIs
    Publication statusPublished - 12 Nov 2014

    Keywords

    • density functional theory
    • grain boundaries
    • Graphene
    • scanning tunneling microscopy
    • scanning tunneling spectroscopy

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