Superlubricity, a cutting-edge concept that eliminates energy losses caused by friction and wear, holds significant promise for enhancing the lifespan of components and promoting carbon neutrality in microelectromechanical systems. However, achieving superlubricity of WS₂ on silicon surfaces and elucidating its underlying mechanisms remain challenging. Here, we investigate the electronic properties and atomic-scale friction of WS₂ micro/nano-elements on silicon-based surfaces using first-principles calculations based on density-functional theory. Our results demonstrate that the graphite/WS₂ heterostructures on silicon substrates can achieve an average friction coefficient as low as 10⁻³, primarily attributed to the elimination of edge pinning effects. However, under humid conditions, the superlubricity between graphite/WS₂ interfaces is disrupted due to the formation of H-S covalent bonds, which increase interfacial adhesion. This work provides novel insights into the lubrication mechanisms of WS₂ and significantly advances our understanding of the frictional properties of two-dimensional materials, highlighting their potential applications in various technological fields.

中文翻译：

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WS2/Graphite 界面中的超润滑机制：硅基衬底的第一性原理研究


超润滑性是一种尖端概念，可消除摩擦和磨损引起的能量损失，在延长部件使用寿命和促进微机电系统碳中和方面具有重要前景。然而，在硅表面实现 WS₂ 的超润滑性并阐明其潜在机制仍然具有挑战性。在这里，我们使用基于密度泛函理论的第一性原理计算来研究 WS₂ 微/纳米元素在硅基表面上的电子性质和原子级摩擦。我们的结果表明，硅衬底上的石墨/WS₂ 异质结构可以达到低至 ^10-3 的平均摩擦系数，这主要归因于消除了边缘固定效应。然而，在潮湿条件下，由于 H-S 共价键的形成，石墨/WS₂ 界面之间的超润滑性被破坏，这增加了界面粘附力。这项工作为 WS₂ 的润滑机制提供了新的见解，并显着促进了我们对二维材料摩擦特性的理解，突出了它们在各个技术领域的潜在应用。