Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Rotational Grain Boundaries in Graphene



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


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.
Physical Review B


graphene, defects, grain boundaries, STM imagery


Cockayne, E. , Rutter, G. , Guisinger, N. , Crain, J. , Stroscio, J. and , P. (2011), Rotational Grain Boundaries in Graphene, Physical Review B, [online], (Accessed April 17, 2024)
Created May 12, 2011, Updated February 19, 2017