A plethora of two-dimensional (2D) materials have been introduced in physics and engineering in the past two decades. Their robust, membranelike sheets permit (mostly require) deposition, giving rise to solid-solid dry interfaces whose mobility, pinning, and general tribological properties under shear stress are currently being understood and controlled, both experimentally and theoretically. In this Colloquium simulated case studies of twisted graphene systems are used as a prototype workhorse tool to demonstrate and discuss the general picture of 2D material interface sliding. First highlighted is the crucial mechanical difference, often overlooked, between small and large incommensurabilities, which corresponds to, for example, small and large twist angles in graphene interfaces. In both cases, focusing on flat, structurally lubric or “superlubric” geometries, the generally separate scalings with the area of static friction in pinned states and of kinetic friction during sliding are elucidated and reviewed, tangled as they are with the effects of velocity, temperature, load, and defects. The roles of island boundaries and elasticity are also discussed, and compared when possible to results in the literature for systems other than graphene. It is proposed that the resulting picture of pinning and sliding should be applicable to interfaces in generic 2D materials that are of importance for the physics and technology of existing and future bilayer and multilayer systems.

中文翻译：

---

座谈会：结构润滑二维材料界面中的滑动和钉扎

在过去的二十年里，物理学和工程学中引入了大量的二维 (2D) 材料。它们坚固的膜状片材允许（大多数需要）沉积，从而产生固-固干界面，其在剪切应力下的移动性、钉扎和一般摩擦学特性目前正在实验和理论上得到理解和控制。在本次研讨会中，扭曲石墨烯系统的模拟案例研究被用作原型主力工具，以演示和讨论二维材料界面滑动的概况。首先强调的是小不可通约性和大不可通约性之间经常被忽视的关键机械差异，例如，这对应于石墨烯界面中的小和大扭转角。在这两种情况下，重点关注平面、结构润滑或“超润滑”几何形状，阐明和回顾了固定状态下静摩擦面积和滑动过程中动摩擦面积的通常独立的比例关系，它们与速度的影响相互纠缠在一起，温度、负载和缺陷。还讨论了岛边界和弹性的作用，并在可能的情况下与石墨烯以外的系统的文献结果进行比较。建议所得到的钉扎和滑动图像应适用于通用二维材料中的界面，这对于现有和未来双层和多层系统的物理和技术非常重要。