Molecular dynamics simulation of lateral ultrasonic excitation in atomic-scale friction

The normal and lateral (in the sliding direction) vibration can achieve 'dynamic superlubricity' at the atomic scale which has been studied and proved by other researchers. In this study, we have found that the lateral excitation (perpendicular to the sliding direction) which has rarely been studied before can also reduce the average friction force greatly. By utilizing the tip path on the interaction potential energy surface and plotting the interaction potential energy as a function of support position, we elucidated the reason of dynamic superlubricity caused by lateral excitation. The details of the lateral excitation at the atomic scale friction have been demonstrated by molecular dynamics simulations and numerical computation based on the Prandtl-Tomlinson model. This study can increase the understanding of the ultrasonic vibration excitation at atomic scale friction.