Fig. 2: Nano friction experiments under lateral force mode of atomic force microscopy (AFM).
From: Pseudo-Landau levels splitting triggers quantum friction at folded graphene edge
Topographical images and lateral force signals of folded and exposed graphene edges with 4 layers (a) and 14 (b) layers. Inset: height profile along the white dashed line and the thickness of the fold. The ΔFL denotes the increase in lateral force (FL) for the AFM tip climbing the graphene edges. c Curves of the μL versus layer number for folded and exposed edges. Error bars represent the standard deviation obtained by measuring the μL of three different graphene flakes at the same layer number. d Adhesion Fad at folded edges and exposed edges with increasing graphene layers, respectively. Error bars represent the standard deviations obtained by measuring three different locations at the same layer number Scale bars for (a) and (b): 100 nm. e Raman G peaks of exposed and folded graphene edges with the number of layers from 2−18. f G peak frequencies as a function of layer number at the folded and exposed graphene edges. Error bars represent the standard deviations obtained by measuring three different locations at the same layer number. The black dashed lines in (c−f) are the fittings of corresponding data points, and the functional forms and fittings are shown in Supplementary Note 14.
