DataSheet1_Negative or Positive? Loading Area Dependent Correlation Between Friction and Normal Load in Structural Superlubricity.docx

Structural superlubricity (SSL), a state of ultra-low friction between two solid contacts, is a fascinating phenomenon in modern tribology. With extensive molecular dynamics simulations, for systems showing SSL, here we discover two different dependences between friction and normal load by varying the size of the loading area. The essence behind the observations stems from the coupling between the normal load and the edge effect of SSL systems. Keeping normal load constant, we find that by reducing the loading area, the friction can be reduced by more than 65% compared to the large loading area cases. Based on the discoveries, a theoretical model is proposed to describe the correlation between the size of the loading area and friction. Our results reveal the importance of loading conditions in the friction of systems showing SSL, and provide an effective way to reduce and control friction.

结构超润滑（SSL），即两种固体接触间的超低摩擦状态，是现代摩擦学领域中的一个引人入胜的现象。通过对展现结构超润滑特性的系统进行广泛的分子动力学模拟，我们发现，通过改变加载面积的大小，摩擦与法向载荷之间存在两种不同的依赖关系。这些观察背后的本质源于法向载荷与结构超润滑系统边缘效应之间的耦合。在保持法向载荷恒定的条件下，我们发现通过减小加载面积，摩擦可以比大加载面积情况降低超过65%。基于这些发现，我们提出了一种理论模型，用以描述加载面积大小与摩擦之间的相关性。我们的研究揭示了加载条件在展现结构超润滑特性的系统摩擦中的重要性，并提供了有效降低和控制摩擦的方法。