International School for Advanced Studies (SISSA), Via Bonomea 265, 34136 Trieste, Italy.
Nanoscale. 2018 Jan 25;10(4):2073-2080. doi: 10.1039/c7nr07857a.
Graphene nanoribbons (GNRs) physisorbed on a Au(111) surface can be picked up, lifted at one end, and made to slide by means of the tip of an atomic-force microscope. The dynamic transition from smooth sliding to multiple stick-slip regimes, the pushing/pulling force asymmetry, the presence of pinning, and its origin are real frictional processes in a nutshell, in need of a theoretical description. To this purpose, we conduct classical simulations of frictional manipulations of a 30 nm-long GNR, one end of which is pushed or pulled horizontally while held at different heights above the Au surface. These simulations allow us to clarify theoretically the emergence of stick-slip originating from the short 1D edges rather than the 2D "bulk", the role of adhesion, of lifting, and of graphene bending elasticity in determining the GNR sliding friction. The understanding obtained in this simple context is of additional value for more general cases.
在 Au(111)表面上物理吸附的石墨烯纳米带（GNRs）可以被拾起、一端提起并通过原子力显微镜的尖端使其滑动。从平稳滑动到多个粘滑状态的动态转变、推/拉力的不对称性、钉扎的存在及其起源，简而言之，都是实际的摩擦过程，需要理论描述。为此，我们对 30nm 长的 GNR 的摩擦操作进行了经典模拟，其中 GNR 的一端在不同高度保持在 Au 表面上方时被水平推动或拉动。这些模拟允许我们从短的 1D 边缘而不是 2D“体”中理论上阐明粘滑的出现，阐明附着力、提升和石墨烯弯曲弹性在确定 GNR 滑动摩擦中的作用。在这种简单的情况下获得的理解对于更一般的情况具有额外的价值。
