STS on a graphene nanoisland on Ir(111). (a) A 70 × 70 nm2 CC-STM image of G islands on Ir(111) (V
= − 0.05 V, Iset = 1 nA). The inset is a CC-STM image of a zoom-in of the G lattice with an illustration of the hexagonal C ring (red circles) and lattice vectors (black arrows) (V
= 0.05 V, Iset = 1 nA). Crystallographic directions of the Ir substrate are denoted at the bottom-left side, as deduced from atomically resolved STM images of the substrate. (b) The G island indicated by the dashed circle in (a). (c) It gives the line profile along the long axis of the island in (b). (d,e,f) The dI/dV maps of the island in (b), measured at V
denoted at the bottom-left corner of each image. (g) STS spectra measured at the positions a to c in (b).