Borophene: Provides the Possibility to Observe the Behavior of a Negative Friction Coefficient in a Rigid Interface

From the classic Amonton’s law, there was a positive correlation between the frictional force and the normal load when a solid surface slid. However, the negative coefficient of friction behavior found in the experiment was completely different from our perception, that is, the negative correlation between friction and normal load. Since the current experimental observations and theoretical calculation predictions of the negative friction coefficient are mostly based on the deformation of the sample layer during the friction process or the participation of lubricants such as water film, it is necessary to study the behavior of the negative friction coefficient in a purely rigid system. Through first-principles calculations, we simulated the probe in the non-jump-to-contact area and observed the behavior of the negative friction coefficient in the non-deformed borophene rigid interface, and it can be combined with traditional atomic force microscope experiments to provide experimental results. The observation of the negative friction coefficient behavior of the rigid interface provides feasibility and guidance.