Wang Jianjun, Li Lin, Shen Ziting, Guo Peng, Li Meng, Zhao Bin, Fang Lili, Yang Linfeng
Computational and Design Center for Low-dimensional Quantum Material, and College of Science, Zhongyuan University of Technology, Zhengzhou 450007, China.
Delivery Devices and Connected Solutions, Eli Lilly and Company, Indianapolis, IN 46285, USA.
Materials (Basel). 2018 Dec 4;11(12):2462. doi: 10.3390/ma11122462.
Dispersion-corrected density functional theory (DFT) calculations reveal that the layered electride of dicalcium nitride (Ca₂N) exhibits stronger interlayer binding interactions but lower interlayer friction behavior than that of traditional layered lubricants weakly bonded by van der Waals (vdW) interactions, such as graphite, -BN, and MoS₂. These results are attributed to the two-dimensional (2D) homogeneous conduction electrons distribution in the middle of the interlayer space of Ca₂N, which yields a smooth sliding barrier and hence ultralow friction behavior. The interesting results obtained in this study have not only broadened the scope of 2D solid lubricants but also enriched the physical understanding of ultralow friction mechanism for 2D systems.
色散校正密度泛函理论（DFT）计算表明，氮化二钙（Ca₂N）层状电子化物表现出比传统由范德华（vdW）相互作用弱键合的层状润滑剂（如石墨、-BN和MoS₂）更强的层间结合相互作用，但层间摩擦行为更低。这些结果归因于Ca₂N层间空间中部的二维（2D）均匀传导电子分布，这产生了一个光滑的滑动势垒，从而导致超低摩擦行为。本研究中获得的有趣结果不仅拓宽了二维固体润滑剂的范围，还丰富了对二维系统超低摩擦机制的物理理解。
