A Computational Study of Cluster Dynamics in Structural Lubricity: Role of Cluster Rotation
A Computational Study of Cluster Dynamics in Structural Lubricity: Role of Cluster Rotation
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DOI：
10.1007/s11249-023-01785-6
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发表时间：
2023-03
影响因子：
3.2
通讯作者：
W. H. Oo;M. Baykara;Hongyu Gao
中科院分区：
文献类型：
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作者：
W. H. Oo;M. Baykara;Hongyu Gao
我们提出了金簇和高度定向热解石墨基底之间滑动的计算研究，该材料系统由于结构润滑而表现出超低摩擦。通过分子动力学，发现团簇在操纵过程中可能由于弹性不稳定性而发生自发旋转，从而由于界面不可通约性增强而导致摩擦力减弱。在自由簇的情况下，剪切应力表现出对尖端簇相互作用的强度的非单调依赖性，由此刚性簇经历几乎恒定的剪切应力。最后，研究表明，抑制团簇最外层的平移自由度可以部分消除面外声子振动，从而减少符合斯托克斯阻尼的能量耗散。预计本文提出的研究获得的物理见解将增强对结构润滑接触处操纵实验的控制和解释。
We present a computational study of sliding between gold clusters and a highly oriented pyrolytic graphite substrate, a material system that exhibits ultra-low friction due to structural lubricity. By means of molecular dynamics, it is found that clusters may undergo spontaneous rotations during manipulation as a result of elastic instability, leading to attenuated friction due to enhanced interfacial incommensurability. In the case of a free cluster, shear stresses exhibit a non-monotonic dependency on the strength of the tip-cluster interaction, whereby rigid clusters experience nearly constant shear stresses. Finally, it is shown that the suppression of the translational degrees of freedom of a cluster’s outermost-layer can partially annihilate out-of-plane phonon vibrations, which leads to a reduction of energy dissipation that is in compliance with Stokesian damping. It is projected that the physical insight attained by the study presented here will result in enhanced control and interpretation of manipulation experiments at structurally lubric contacts.