Figure 4: Rewritable friction on monolayer graphene. | Nature Communications

Figure 4: Rewritable friction on monolayer graphene.

From: Switchable friction enabled by nanoscale self-assembly on graphene

Figure 4

(a) Cartoon illustrating the response of the striped adsorbates to the scanning tip. At low normal force, the tip minimally disturbs the stripes as it scans the surface and the stripe structure rapidly heals. At high normal force, the stripe structure is heavily disturbed, creating a new stripe domain in the wake of the scanning tip. (b) Summary of our scanning modes. For imaging, we rapidly scan the cantilever back and forth at low normal force, while slowly moving it in the direction perpendicular to the fast scan axis. The erasing mode is identical, but at high normal force. For a brush stroke, we raster-scan the cantilever such that the tip only moves in one direction when in contact with the sample. After scanning each line, we lift the cantilever, move it to the start of the next line and touch down again. (c) Domain switching as a function of scan angle on the monolayer flake studied in Fig. 1, rotated as in Fig. 1a–c. The image shown is a collage of 12 transverse force images, each taken after executing a single 3 μm by 1 μm brush stroke on a canvas composed initially of a single domain. For each canvas domain we show four brush strokes nearly parallel with the canvas stripes, where each brush stroke is directed radially outward from the origin of the semicircle. The brush strokes steer the canvas domain towards the domain whose stripes are next nearest the brush axis. Scale bar, 3 μm. (d) Transverse force image immediately after writing block letters ‘S’ and ‘U’ in domains III and I, respectively, on a canvas of domain II (same flake and orientation as in a). The block letter ‘S’ was written by ‘erasing’, whereas the ‘U’ was written using brush strokes. Scale bar, 3 μm. (e) Transverse force image of the same area, taken 90 min later. The ‘S’ (domain III) has expanded into the canvas, while the ‘U’ (domain I) has decayed.

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