Superlubric Sliding of Graphene Nanoflakes on Graphene
Superlubric Sliding of Graphene Nanoflakes on Graphene
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DOI：
10.1021/nn305722d
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发表时间：
2013-02-01
期刊：
影响因子：
17.1
通讯作者：
Salmeron, Miquel
中科院分区：
文献类型：
--
作者：
Feng, Xiaofeng;Kwon, Sangku;Salmeron, Miquel
石墨和石墨烯的润滑性能已经通过摩擦力显微镜尖端对着它们滑动来深入研究，以了解所观察到的低摩擦的起源。相比之下，自由石墨烯层的相对运动仍然知之甚少。在这里，我们报告了石墨烯纳米片（GNF）在石墨烯表面上的滑动行为的研究。使用扫描隧道显微镜，我们发现，GNF显示出轻便的平移和旋转运动之间的相称的初始和最终状态在温度低至5 K。该运动通过薄片从与下面的石墨烯层（超润滑状态）相称到不相称的配准的尖端诱导的转变开始，随后快速滑动直到到达另一个相称的位置。与直觉相反的是，薄片的平均滑动距离在5 K时比在77 K时大，这表明热波动很可能触发它们从超润滑回到相称基态的转变。
The lubricating properties of graphite and graphene have been Intensely studied by sliding a frictional force microscope tip against them to understand the origin of the observed low friction. In contrast, the relative motion of free graphene layers remains poorly understood. Here we report a study of the sliding behavior of graphene nanoflakes (GNFs) on a graphene surface. Using scanning tunneling microscopy, we found that the GNFs show facile translational and rotational motions between commensurate initial and final states at temperatures as low as 5 K. The motion is initiated by a tip-induced transition of the flakes from a commensurate to an Incommensurate registry with the underlying graphene layer (the superlubric state), followed by rapid sliding until another commensurate position is reached. Counterintuitively, the average sliding distance of the flakes is larger at 5 K than at 77 K, indicating that thermal fluctuations are likely to trigger their transitions from superlubric back to commensurate ground states.