Gao Wang, Tkatchenko Alexandre
Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195, Berlin, Germany.
Phys Rev Lett. 2015 Mar 6;114(9):096101. doi: 10.1103/PhysRevLett.114.096101. Epub 2015 Mar 2.
The interlayer sliding potential of multilayered hexagonal boron nitride (h-BN) and graphene is investigated using density-functional theory including many-body van der Waals (vdW) interactions. We find that interlayer sliding constraints can be employed to tune the contribution of electrostatic interactions and dispersive forces to the sliding energy profile, ultimately leading to different sliding pathways in these two materials. In this context, vdW interactions are found to contribute more to the interlayer sliding potential of polar h-BN than they do in nonpolar graphene. In particular, the binding energy, the interlayer distance, and the friction force are found to depend sensitively on the number of layers. By comparing with the experimental findings, we identify sliding pathways which rationalize the observed reduced friction for thicker multilayers and provide quantitative explanation for the anisotropy of the friction force.
利用包含多体范德华（vdW）相互作用的密度泛函理论，研究了多层六方氮化硼（h-BN）和石墨烯的层间滑动势。我们发现，可以利用层间滑动约束来调节静电相互作用和色散力对滑动能量分布的贡献，最终导致这两种材料中出现不同的滑动路径。在这种情况下，发现vdW相互作用对极性h-BN的层间滑动势的贡献比在非极性石墨烯中的贡献更大。特别是，发现结合能、层间距离和摩擦力对层数敏感依赖。通过与实验结果比较，我们确定了滑动路径，这些路径合理地解释了观察到的较厚多层膜摩擦力降低的现象，并为摩擦力的各向异性提供了定量解释。
