Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
J Phys Condens Matter. 2010 Dec 8;22(48):485301. doi: 10.1088/0953-8984/22/48/485301. Epub 2010 Nov 12.
Graphene is a fascinating material not only for technological applications, but also as a test bed for fundamental insights into condensed matter physics due to its unique two-dimensional structure. One of the most intriguing issues is the understanding of the properties of graphene and various substrate materials. In particular, the interfaces between graphene and metal substrates are of critical importance in applications of graphene in integrated electronics, as thermal materials, and in electromechanical devices. Here we investigate the structure and mechanical interactions at a graphene-metal interface through density functional theory (DFT)-based calculations. We focus on copper (111) and nickel (111) surfaces adhered to a monolayer of graphene, and find that their cohesive energy, strength and electronic structure correlate directly with their atomic geometry. Due to the strong coupling between open d-orbitals, the nickel-graphene interface has a much stronger cohesive energy with graphene than copper. We also find that the interface cohesive energy profile features a well-and-shoulder shape that cannot be captured by simple pair-wise models such as the Lennard-Jones potential. Our results provide a detailed understanding of the interfacial properties of graphene-metal systems, and help to predict the performance of graphene-based nanoelectronics and nanocomposites. The availability of structural and energetic data of graphene-metal interfaces could also be useful for the development of empirical force fields for molecular dynamics simulations.
石墨烯不仅在技术应用方面令人着迷，而且由于其独特的二维结构，也是深入了解凝聚态物理基本原理的理想平台。其中一个最引人关注的问题是理解石墨烯和各种基底材料的性质。特别是，石墨烯与金属基底之间的界面在石墨烯在集成电子、热材料和机电设备中的应用中至关重要。在这里，我们通过基于密度泛函理论（DFT）的计算研究了石墨烯-金属界面的结构和力学相互作用。我们专注于铜（111）和镍（111）表面与单层石墨烯的结合，发现它们的内聚能、强度和电子结构与它们的原子几何形状直接相关。由于开放 d 轨道之间的强耦合，镍-石墨烯界面与石墨烯的内聚能比铜要强得多。我们还发现，界面内聚能的分布特征是一个山谷和肩部形状，这不能用简单的对势模型（如 Lennard-Jones 势）来捕捉。我们的结果提供了对石墨烯-金属体系界面性质的详细理解，有助于预测基于石墨烯的纳米电子学和纳米复合材料的性能。石墨烯-金属界面的结构和能量数据的可用性也可能有助于开发分子动力学模拟的经验力场。
