Departament de Química Física and Institut de Química Teòrica i Computacional (IQTCUB), Universitat de Barcelona, c∕ Martí i Franquès 1, 08028 Barcelona, Spain.
J Chem Phys. 2013 Jun 28;138(24):244701. doi: 10.1063/1.4807855.
Graphene-metal contacts have emerged as systems of paramount importance in the synthesis of high-quality and large-size patches of graphene and as vital components of nanotechnological devices. Herein, we study the accuracy of several density functional theory methods using van der Waals functionals or dispersive forces corrections when describing the attachment of graphene on Ni(111). Two different experimentally observed chemisorption states, top-fcc and bridge-top, were put under examination, together with the hcp-fcc physisorption state. Calculated geometric, energetic, and electronic properties were compared to experimental data. From the calculations, one finds that (i) predictions made by different methodologies differ significantly and (ii) optB86b-vdW functional and Grimme dispersion correction seem to provide the best balanced description of stability of physisorption and chemisorption states, the attachment strength of the latter on Ni(111) surface, the graphene-Ni(111) separation, and the bandstructure of chemisorbed graphene. The collation suggests that accurate and affordable theoretical studies on technologies based on graphene-metal contacts are already at hand.
石墨烯-金属接触已成为合成高质量、大面积石墨烯的重要系统，也是纳米技术器件的重要组成部分。在此，我们研究了几种密度泛函理论方法在描述石墨烯在 Ni(111)上附着时使用范德华函数或色散力修正的准确性。我们对两种不同的实验观察到的化学吸附态，顶 fcc 和桥顶，以及 hcp-fcc 物理吸附态进行了研究。计算了几何、能量和电子性质，并与实验数据进行了比较。从计算结果中可以发现：（i）不同方法学的预测存在显著差异；（ii）optB86b-vdW 泛函和 Grimme 色散修正似乎能够最好地平衡描述物理吸附和化学吸附态的稳定性、后者在 Ni(111)表面上的附着强度、石墨烯-Ni(111)的分离以及化学吸附石墨烯的能带结构。综上所述，基于石墨烯-金属接触的技术已经可以进行准确且经济实惠的理论研究。
