Third bodies are ubiquitous in meso- and nanoscopic friction pairs. So far, few researchers have investigated their effects on structural superlubric contact which is a promising approach in reducing friction and wear. In this work, using molecular dynamics simulations we find that intercalated molecules, a typical type of third body, have multiple effects in graphite contacts. While for commensurate contacts the friction decreases with the coverage of intercalated molecules in general, for an incommensurate interface a complex dependence is observed. With state-of-the-art detailed analysis, we reveal that with coverage increases, for commensurate contacts the change in contact area accounts for the variation in friction. For incommensurate contacts, the resistance due to the direct interaction between intercalated molecules and the slider dominates the energy dissipation. For both kinds of contacts, complex transitions in the structures and kinetic behaviors of intercalated molecules are observed. Our results provide an overall picture for the effects of intercalated molecules on friction in structural superlubric systems.

中文翻译：

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了解插层分子对结构超润滑接触的影响

第三体在介观和纳米摩擦对中无处不在。迄今为止，很少有研究者研究它们对结构超润滑接触的影响，这是减少摩擦和磨损的一种有前途的方法。在这项工作中，使用分子动力学模拟，我们发现插层分子（一种典型的第三体）在石墨接触中具有多种作用。通常，对于相称的接触，摩擦随着插入分子的覆盖而减小，而对于相称的界面，则观察到复杂的依赖性。通过最新的详细分析，我们发现随着覆盖范围的增加，对于相称的接触，接触面积的变化会导致摩擦力的变化。对于不相称的联系人，由于插层分子和滑块之间直接相互作用而产生的阻力主导了能量耗散。对于两种接触，都可以观察到嵌入分子的结构和动力学行为的复杂转变。我们的结果为插层分子对结构性超润滑系统中的摩擦的影响提供了全面的了解。