In-situ laser-irradiation induced robust macroscale superlubricity

Superlubricity can be realized either by structural incommensurate contact between crystalline surfaces or by creating highly passive surfaces to cancel out the adhesive forces. However, fabricating and maintaining such superlubric surfaces remain challenges, often disabled by surface structural defects or susceptibility to atmospheric environment, which renders superlubricity fragile. Here, we propose a novel strategy of photoelectron superlubricity (PESL), where robust macroscale superlubricity can be achieved in ambient humid environment by in-situ laser-irradiating the contact interface of an amorphous carbon film. We demonstrate that PESL not only exhibits a high resistance to environmental disturbances but also features rapid response. The formation of PESL originates from the laser-irradiation induced formation of nanographene-layered interface and enrichment of photoelectrons at the interface, resulting in a repulsive electric field between the nanographene layers. The discovery of PESL opens a new avenue for achieving superlubricity, and provides novel insights for smart friction and mechanical motion control.