Rotational Grain Boundaries in Graphene

Published

May 12, 2011

Author(s)

Eric J. Cockayne, Gregory M. Rutter, N Guisinger, Jason Crain, Joseph A. Stroscio, Phillip First

Abstract

Defects in graphene are of interest for their effect on electronic transport in this two-dimensional material. Point defects of typically two-fold and three-fold symmetry have long been observed in scanning tunneling microscopy (STM) studies of graphite. In epitaxial graphene grown at high temperatures on mechanically-polished SiC(0001), we observe a 6-fold "flower" defect by STM, with enhanced differential tunnel conductance over the 2 nm extent of the defect. Density functional theory calculations suggest that the defect is a rotational grain boundary made up of five- and seven-membered carbon rings. The observed defect is the smallest member of a family of rotational grain boundaries characterized by two integers, (m,n), which correspond to rotations of the hexagonal lattice within the core of the defect by (n/m)x(60 degrees) with respect to the outside lattice. Simulated STM topographs of the (2,1) rotational defect are in agreement with experiment.

Citation

Physical Review B

Volume

83

Pub Type

Journals

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Keywords

graphene, defects, grain boundaries, STM imagery

Citation

Cockayne, E. , Rutter, G. , Guisinger, N. , Crain, J. , Stroscio, J. and , P. (2011), Rotational Grain Boundaries in Graphene, Physical Review B, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=906586 (Accessed October 8, 2025)