Figure 1.

Experimental characterization of surface conductivities on tMLG samples with twisted interface embedded at different depths. (a) A schematic diagram showing c-AFM measurements on the tMLG surface (right panel) where a constant voltage bias is applied between the conductive tip and the bottom graphite. The figure also shows schematics of the atomic structures of the two atomic layers at the twisted interface before (upper-left panel) and after (lower-left panel) reconstruction. (b) Typical current maps obtained from the twisted 1 L/graphite (with a twist angle of 0.16° ± 0.02°), 2 L/graphite (0.25° ± 0.01°), 3 L/graphite (0.20° ± 0.02°), 6 L/graphite (0.13° ± 0.02°) and 10 L/graphite (0.21° ± 0.04°). The reported current maps are normalized by the averaged current values of the corresponding images. The different stacking regions are highlighted with black dotted triangles, where L and H represent the low and high conductivity domains. Scale bars, 50 nm. (c) The current ratio between H domain and L domain as a function of the embedded depth of the twisted interface for different tMLG samples. The embedded depth can also be expressed as the number of top graphene layers above the twisted interface. The error bar represents the standard deviation of different samples or different current images.