基于滑动势能面的二维材料原子尺度摩擦行为的量化计算

发布时间：2018-10-24 14:38

【摘要】：近年来,二维材料优异的摩擦特性成为人们关注的焦点,然而目前缺乏理论上对其摩擦力进行快速、有效、精确的计算预测方法.本文提出采用密度泛函理论计算真实体系的滑动势能面,利用得到的"数值型势能面"替代传统的解析势函数,并结合Prandtl-Tomlinson模型,量化求解具有复杂形状势能面的真实二维材料体系的摩擦行为.基于该方法,揭示了原子力显微镜实验中观察到的石墨烯Moire纹超晶格结构的双周期"黏-滑"摩擦现象;理论预测了二维材料异质结构的层间超低摩擦现象,相对于同质材料,其静摩擦力和滑动摩擦力均成数量级降低,发现势能面起伏和驱动弹簧刚度均会影响层间相对滑动路径,进而对层间的摩擦行为产生影响.该方法同样可拓展到其他van der Waals作用主导的界面摩擦体系.
[Abstract]:In recent years, the excellent friction characteristics of two-dimensional materials have become the focus of attention. However, there is a lack of fast, effective and accurate calculation and prediction method for the friction force of two-dimensional materials. In this paper, the density functional theory is used to calculate the sliding potential energy surface of real system. The "numerical potential energy surface" is used to replace the traditional analytic potential function, and the Prandtl-Tomlinson model is combined. The friction behavior of a real two-dimensional material system with complex shape potential energy surface is quantitatively solved. Based on this method, the phenomenon of double-period "stick-slip" friction of graphene Moire grain superlattice structure observed in atomic force microscope is revealed, and the phenomenon of ultra-low friction between layers of two-dimensional heterostructure is predicted theoretically, compared with that of homogeneous material. The static friction force and sliding friction force decrease by an order of magnitude. It is found that both the fluctuation of potential energy surface and the stiffness of driving spring will affect the relative sliding path between layers, and then affect the friction behavior between layers. The method can also be extended to other interface friction systems dominated by van der Waals action.
【作者单位】：清华大学摩擦学国家重点实验室;南京航空航天大学航天学院仿生结构与材料防护研究所;北京科技大学腐蚀与防护中心;
【基金】：国家自然科学基金(批准号:51422504,51505217,51527901)资助的课题~~
【分类号】：O482.1

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