Abstract The deformation induced atomic-scale stick-slip behaviors are unique and prominent friction characteristics of atomically thin two-dimensional (2D) materials. Here, the deformation induced atomic-scale frictional characteristics of atomically thin 2D materials under different load were explored at different velocity using atomic force microscopy. The evolution of contact quality and puckering forming play important role in atomic-scale frictional characteristics of 2D materials. The critical load was proposed for the strengthening effect at transient period of atomic-scale friction. The velocity-dependent evolution of contact quality affects the strengthening effect when the normal load is less than the critical load. Strengthening degree and distance increase with the increase of the normal load because of high puckering and strong interfacial bonding when the load exceeds the critical load. The suspended 2D materials on asperities of rough substrate possess stronger strengthening effect than smooth substrate because of large deformation space and flexibility. The stick time in stick-slip behavior elongated with the increase of load as the lattice of 2D materials on rough substrate is locally distorted by large deformation under high load. The correlation between the strengthening effect and friction of 2D materials could potentially provide deep insights into the tribological behavior of atomically thin 2D materials.

中文翻译：

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原子级薄二维材料的变形诱导原子级摩擦特性

摘要 变形引起的原子级粘滑行为是原子级薄二维 (2D) 材料独特而突出的摩擦特性。在这里，使用原子力显微镜以不同的速度探索了原子级薄二维材料在不同载荷下的变形诱导的原子级摩擦特性。接触质量和起皱形成的演变在二维材料的原子级摩擦特性中起着重要作用。提出临界载荷是为了增强原子级摩擦瞬态期间的强化效果。当法向载荷小于临界载荷时，接触质量的速度相关演化会影响强化效果。当载荷超过临界载荷时，由于高起皱和强界面结合，强化程度和距离随着法向载荷的增加而增加。粗糙基体的凹凸不平处的二维材料由于变形空间大和柔韧性好，比光滑基体具有更强的强化效果。粘滑行为的粘滞时间随着载荷的增加而延长，因为粗糙基板上的二维材料的晶格在高载荷下因大变形而局部扭曲。二维材料的强化效果与摩擦力之间的相关性可能为深入了解原子级薄二维材料的摩擦学行为提供了可能。粗糙基体的凹凸不平处的二维材料由于变形空间大和柔韧性好，比光滑基体具有更强的强化效果。粘滑行为的粘滞时间随着载荷的增加而延长，因为粗糙基板上的二维材料的晶格在高载荷下因大变形而局部扭曲。二维材料的强化效果与摩擦力之间的相关性可能为深入了解原子级薄二维材料的摩擦学行为提供了可能。粗糙基体的凹凸不平处的二维材料由于变形空间大和柔韧性好，比光滑基体具有更强的强化效果。粘滑行为的粘滞时间随着载荷的增加而延长，因为粗糙基板上的二维材料的晶格在高载荷下因大变形而局部扭曲。二维材料的强化效果与摩擦力之间的相关性可能为深入了解原子级薄二维材料的摩擦学行为提供了可能。