Grain Boundary Loops in Graphene

Abstract

Topological defects can affect the physical properties of graphene in unexpected ways. Harnessing their influence may lead to enhanced control of both material strength and electrical properties. Here we present a new class of topological defects in graphene composed of a rotating sequence of dislocations that close on themselves, forming grain boundary loops that either conserve the number of atoms in the hexagonal lattice or accommodate vacancy/interstitial reconstruction, while leaving no unsatisfied bonds. One grain boundary loop is observed as a "flower" pattern in scanning tunneling microscopy (STM) studies of epitaxial graphene grown on SiC(0001). We show that the flower defect has the lowest energy per dislocation core of any known topological defect in graphene, providing a natural explanation for its growth via the coalescence of mobile dislocations.

23 pages, 7 figures. Revised title; expanded; updated references

References in corpus (11)

• The electronic properties of graphene
• Ultrathin epitaxial graphite: 2D electron gas properties and a route toward graphene-based nanoelectronics
• Electronic transport in polycrystalline graphene
• Topological Defects in Graphene: Dislocations and Grain Boundaries
• Monovalent impurities on graphene: midgap states and migration barriers
• Quasiparticle Chirality in Epitaxial Graphene Probed at the Nanometer Scale
• Effect of a single impurity on the local density of states in monolayer and bilayer graphene
• Defect Engineering: Graphene Gets Designer Defects
• Local density of states and scanning tunneling currents in graphene
• Noise color and asymmetry in stochastic resonance with silicon nanomechanical resonators
• Charged defects in graphene and the ionicity of hexagonal boron nitride in direct images