范德华界面处的边缘主导扭转力学
Edge-Dominated Twist Mechanics at van der Waals Interfaces
- Tsinghua Shenzhen International Graduate School, Tsinghua University（清华大学深圳国际研究生院）
- University of Science and Technology of China（中国科学技术大学）
- Tel Aviv University（特拉维夫大学）
- Research Institute of Tsinghua University in Shenzhen（清华大学深圳研究院）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
本研究通过实验和原子模拟揭示范德华界面扭转由边缘主导屈服机制控制，扭矩随接触面积线性变化，与滑动摩擦的体相机制截然不同，为微纳器件设计提供关键见解。
AI中文摘要：
尽管扭转在调控范德华（vdW）界面物理性质中起着关键作用，但控制扭转响应的力学机制仍知之甚少。在此，我们在统一的实验框架内探究了同质和异质vdW界面处的扭转力学及其滑动行为。对于这两种系统，峰值扭矩几乎随接触面积线性变化，这与线弹性和刚性模型的预测形成对比。值得注意的是，尽管两种界面的滑动摩擦力因标度律不同而相差超过三个数量级，但相应的扭矩遵循相同的线性标度，且仅相差约二十倍。大规模原子模拟揭示了一种边缘主导的扭转运动屈服机制，其中弹性重构将有效承载区域移向边缘，消除了接触内部的扭矩贡献。这一机制与主导平移滑动的体相介导应力传递形成对比，其根源在于两种运动模式固有的加载几何差异：扭转加载需要周边驱动，而滑动则允许中心驱动加载。这种对称性强制的差异表明，在vdW界面处，平移性质和扭转性质不能相互预测，为动态可重构微纳机电系统的设计提供了关键见解。
英文摘要：
Despite the pivotal role of twist in modulating physical properties at van der Waals (vdW) interfaces, the mechanics governing torsional response remain poorly understood. Here, we probe twist mechanics at homo- and heterogeneous vdW interfaces, together with their sliding behaviors within a unified experimental framework. For both systems, the peak torque scales nearly linearly with contact area, in contrast to predictions from linear elastic and rigid models. Remarkably, while the sliding friction of the two interfaces diverges by over three orders of magnitude owing to different scaling laws, the corresponding torque follows the same linear scaling and differs by only about twenty-fold. Large-scale atomistic simulations reveal an edge-dominated yielding mechanism for torsional motion, wherein elastic reconstruction shifts the effective load-bearing region toward the edges, eliminating torque from the contact interior. This mechanism contrasts with the bulk-mediated stress transmission governing translational sliding, a distinction rooted in the different loading geometries inherent to the two motion modes, where torsional loading necessitates perimeter actuation, whereas sliding enables center-driven loading. This symmetry-imposed divergence demonstrates that translational and torsional properties cannot be predicted from one another at vdW interfaces, providing critical insights for the design of dynamically reconfigurable micro- and nanoelectromechanical devices.
