A comparison study between the Lennard-Jones and DRIP potentials for friction of graphene layers
A comparison study between the Lennard-Jones and DRIP potentials for friction of graphene layers
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DOI：
10.1016/j.commatsci.2020.109723
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发表时间：
2020-03
影响因子：
3.3
通讯作者：
Huyan Li;Woo Kyun Kim
中科院分区：
文献类型：
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作者：
Huyan Li;Woo Kyun Kim
石墨烯是一种很有前途的固体润滑剂，特别是对于小长度尺度的设备，如纳米/微机电系统。分子动力学等原子模拟方法是研究石墨烯层间摩擦行为的常用工具，准确描述层间相互作用对石墨烯摩擦性能的预测至关重要。在分子动力学模拟多层石墨烯结构摩擦滑动过程中，采用Lennard-Jones（LJ）势和DRIP势两种原子间相互作用势研究了石墨烯层间的相互作用.虽然这两个潜在的有相同的吸引力的相互作用，DRIP模型的排斥相互作用的注册表依赖的修改器考虑横向距离和二面角。滑动模拟模仿原子力显微镜实验，并在Z字形（ZZ）和扶手椅（AC）方向进行。仿真结果表明，在两个滑动方向上，DRIP模型的摩擦力都比LJ模型的摩擦力大一个数量级左右。事实证明，DRIP中排斥项的修改引入了额外的能量波纹，增加了摩擦力。此外，它被发现，滑动方向是另一个重要因素的摩擦力的石墨烯层，使在LJ和DRIP模型中的摩擦力在AC滑动方向上是大约两到三倍大的ZZ滑动。
Graphene is a promising solid lubricant, in particular for small-length scale devices such as nano/micro-electro-mechanical systems. Atomistic simulations such as molecular dynamics is a popular tool to study the frictional behaviors of graphene layers and it is of critical importance to accurately describe the interlayer interactions in order to give a reliable prediction on the friction of graphene. In this study, the interlayer interactions between graphene layers are examined by using two interatomic potentials, Lennard-Jones (LJ) potential and dihedral-angle-corrected registry-dependent interlayer (DRIP) potential, in the molecular dynamics simulations of friction sliding of multilayer graphene structures. While both potentials have the identical attractive interactions, DRIP models the repulsive interaction by registry-dependent modifiers considering transverse distance and dihedral angle. The sliding simulations mimic the atomic force microscope experiment and are carried out in the zigzag (ZZ) and armchair (AC) directions. The simulation results reveal that the friction forces of the DRIP models are about one order of magnitude larger than those of the LJ models in both sliding directions. It turns out that the modification of the repulsive term in DRIP introduces additional energy corrugations which increase the friction force. Moreover, it is found that the sliding direction is another important factor on friction force of graphene layers so that in both LJ and DRIP models the friction force in the AC sliding direction is about two to three times larger than that of the ZZ sliding.