Structural and electronic properties of an ordered grain boundary formed by separated (1,0) dislocations in graphene.

We present an investigation of the structural and electronic properties of an ordered grain boundary (GB) formed by separated pentagon-heptagon pairs in single-layer graphene/SiO2 using scanning tunneling microscopy/spectroscopy (STM/STS), coupled with density functional theory (DFT) calculations. It is observed that the pentagon-heptagon pairs, i.e., (1,0) dislocations, form a periodic quasi-one-dimensional chain. The (1,0) dislocations are separated by 8 transverse rows of carbon rings, with a period of ∼2.1 nm. The protruded feature of each dislocation shown in the STM images reflects its out-of-plane buckling structure, which is supported by the DFT simulations. The STS spectra recorded along the small-angle GB show obvious differential-conductance peaks, the positions of which qualitatively accord with the van Hove singularities from the DFT calculations.