标题： 化学摩擦与超润滑性：朋友还是敌人？ 显示英文标题

标题： Chemifriction and Superlubricity: Friends or Foes?

摘要： 化学摩擦的机制，即界面键合在缺陷扭曲石墨烯界面摩擦中的贡献，是通过完全原子化的机器学习分子动力学模拟揭示的。这涉及连续的键形成和断裂的随机事件，这些事件在空间上是分离的但不一定相互独立。发现了一种独特的剪切诱导层间原子转移修复机制，可以用来设计一个磨合过程以恢复超润滑滑动。这种机制应表现为负微分摩擦系数，在中等法向载荷下预期会出现。开发了一个物理驱动的表观模型，以预测实验相关滑动速度范围内的化学摩擦效应。这使我们能够识别出摩擦应力随滑动速度增加而出现对数增加和对数减少之间的明显转变。虽然仅在均质石墨烯界面中得到演示，类似的机制预计也会出现在其他均质或非均质缺陷二维材料界面中。 显示英文摘要

摘要： The mechanisms underlying chemifriction, i.e. the contribution of interfacial bonding to friction in defected twisted graphene interfaces are revealed using fully atomistic machine-learning molecular dynamics simulations. This involves stochastic events of consecutive bond formation and rupture, that are spatially separated but not necessarily independent. A unique shear-induced interlayer atomic transfer healing mechanism is discovered that can be harnessed to design a run-in procedure to restore superlubric sliding. This mechanism should be manifested as negative differential friction coefficients that are expected to emerge under moderate normal loads. A physically motivated phenomenological model is developed to predict the effects of chemifriction in experimentally relevant sliding velocity regimes. This allows us to identify a distinct transition between logarithmic increase and logarithmic decrease of frictional stress with increasing sliding velocity. While demonstrated for homogeneous graphene interfaces, a similar mechanism is expected to occur in other homogeneous or heterogeneous defected two-dimensional material interfaces.