Figure 2. Subnanometre-gap distance dependence of FL-MoS₂-gold tip interaction with sub-Angstrom control.

(a) Force-displacement curve measured by AFM (circles) and linear fit (red line) of the contact line. Three tip-sample interaction moments are depicted: (i) snap to contact; (ii) vdW contact; (iii) contact line. (b) Repulsive force after vdW contact. At the MoS₂ breaking point, the distance between Au and S atoms is ~0.24 nm. Dashed rectangle selects the linear range of data used for converting repulsive force into subnanometre tip-sample distance via Lennard-Jones model (red line) in (c). This procedure provides sub-Angstrom control of the tip-sample distance and was used to observe quantum quenching and Schottky-Ohmic transition in FL-MoS₂.