Fig. 2

Spatially resolved 2pp transport measurements. a SEM image of a ballistic ribbon with an overlaid schematic showing a blunt and sharp tip with a scale bar of 300 nm. Inset: STM topography taken after transport measurements (scale bar, 100 nm). b Line scans across the ribbon, directions are indicated in the inset of a. c Conductance G measured for a fixed distance L = 70 nm, while the sharp tip was moved across the ribbon starting from the lower edge (U = 200 mV). Inset: IV-curves measured at bottom, middle and top of the GNR. d The sequence of the channels can be reversibly measured by moving the ohmically contacted tip forward and backward