Electronic superstructures observed by scanning tunneling microscopy on graphene sheet in vicinity of nano-defects of Ir(III) substrate

Two-dimensional electronic and atomic superstructures (SS) on monolayer graphite (graphene) grown on a clean Ir(111) surface were observed near substrate nano-defect sites by scanning tunneling microscopy. These SS were found rotated 30degrees with respect to the undistorted areas (away from defects sites) of the graphene layer with a periodicity of similar to(root3 x root3) a (a = 2.46 Angstrom) and decay over a distance of few nanometers away from the defects. The observed SS were not due to real surface reconstruction, rather they just had an electronic nature.