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|Author(s):||Eric J. Cockayne; Gregory M. Rutter; N Guisinger; Jason Crain; Joseph A. Stroscio; Phillip First;|
|Title:||Rotational Grain Boundaries in Graphene|
|Published:||May 12, 2011|
|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|
|Keywords:||graphene, defects, grain boundaries, STM imagery|
|Research Areas:||Nanoelectronics and Nanoscale Electronics|
|PDF version:||Click here to retrieve PDF version of paper (5MB)|