Graphene sheet with the topological defect. Schematic geometry of the graphene sheet studied in this work. Note the pentagonal defect placed at its centre (in red colour). This structure is connected to two semi-infinite graphene leads, which are partially shown in the figure (red colour).
Jódar et al. Nanoscale Research Letters 2013 8:258 doi:10.1186/1556-276X-8-258