Fig. 5: Investigation of friction influencing factors under applied alternating current using the PT-E and PTT-E models.
a, b Variation of friction with bias voltage amplitude at different temperatures. The sliding velocity is set to 10 nm s−1, and the calculations are based on the tip contact (a) and flat contact configuration (b). The red and blue curves in (a) and (b) represent the calculated results of the PTT-E and PT-E models. c The relationship between the absolute value of atomic force change |ΔFE| and change density redistribution |Δρ| for different interfaces. The green, cyan, orange, and yellow markers represent the calculated results for the Ir/Gr/Ni interface, the Ir/Gr/Ni interface with a layer of Ar atoms as adsorbates, the Ir/Gr/Cu interface, and the Ir/h-BN/Au interface, respectively. d The relationship between friction force and alternating current frequency calculated via PT-E and PTT-E model at 2 nm s−1 (d), 500 nm s−1 (e) and 1000 nm s−1 (f). g The relationship between the AC frequency f corresponding to the minimum friction force and the sliding velocity v obtained from the experiment (gray stars) and calculated using PT-E model (blue triangles) and PTT-E model (red cycles). h–k The schematic of the tip apex sliding along the potential energy surface under different f v−1a. Source data are provided as a Source Data file.
