Extended Data Fig. 2: Friction force imaging.
From: Switching graphitic polytypes in elastically coupled cavities
(a, b) Schematic illustration of lateral photodiode signals and the torsional motion of the AFM tip during forward and backward scans. (c) Map of the lateral signal for forward and backward scans. (d) Line-cut along the dashed line in (c). (e) Friction force as a function of the loading force. (f–h) Examples of friction force calibration maps. (i) Corresponding topography map.
