IBM T. J. Watson Research Center, Yorktown Heights, NY, United States.
Nano Lett. 2011 Sep 14;11(9):3629-33. doi: 10.1021/nl201436b. Epub 2011 Aug 17.
The ballistic conductance through junctions between multilayer graphene films and several different metals is studied using ab initio calculations within the local density approximation. The system consists of films of up to four graphene layers (Bernal stacking) between metallic electrodes, assuming reasonable metal-graphene epitaxial relationships. For some metals, the conductance decays exponentially with increasing number of layers, while for others the conductance saturates with film thickness. This difference in asymptotic behavior stems from the crystal momentum (mis)match between the bulk Fermi-level states in the electrode and those in the film. In contrast, for sufficiently thin films the bonding between the metal and the adjacent graphene layer dominates, giving a metal dependence for graphene similar to that seen experimentally for single-wall carbon nanotubes. Among the metals considered here, we find Pd to be the best for electrodes to films with up to 4 graphene layers.
使用局域密度近似的从头计算方法研究了多层石墨烯薄膜与几种不同金属之间的弹道电导。该系统由至多四层石墨烯薄膜（范德华堆叠）夹在金属电极之间组成，假设金属-石墨烯具有合理的外延关系。对于某些金属，电导随层数的增加呈指数衰减，而对于其他金属，电导随膜厚饱和。这种渐近行为的差异源于电极中体费米能级状态与薄膜中状态之间的晶体动量（失配）。相比之下，对于足够薄的薄膜，金属与相邻石墨烯层之间的键合占主导地位，这使得石墨烯对金属的依赖性与实验中观察到的单壁碳纳米管相似。在所考虑的金属中，我们发现 Pd 是具有至多 4 层石墨烯薄膜的最佳电极材料。
