The electronic structures of novel heterostructures, namely, graphene–Au van der Waals (vdW) interfaces, have been studied using density functional theory. Dispersion-corrected PBE-D2 functionals are used to describe the phonon spectrum and binding energies. Ab initio molecular dynamics simulations reveal that the vdW framework is preserved till 1200 K. Beyond T = 1200 K, a transition of the quasiplanar Au into the three-dimensional cluster-like structure is observed. A dielectric capacitor is designed by placing 1–4 hexagonal boron nitride (h-BN) monolayers between graphene and Au conductive plates. Charge separation between the Au and graphene plates is carried out under the effect of an external field normal to the graphene–h-BN–Au interface. The gravimetric capacitances are computed as C₁ = 7.6 μF/g and C₂ = 3.2 μF/g for h-BN bilayers with the Au–graphene heterostructures. The capacitive behavior shows strong deviations from the classical charging models and exemplifies the importance of quantum phenomenon at short contacts, which eventually nullifies at large interelectrode distances. The graphene–Au interface is predicted to be an exciting vdW heterostructure with a potential application as a dielectric capacitor.

中文翻译：

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二维石墨烯-金界面用作介电电容器的稳健模板

已经使用密度泛函理论研究了新型异质结构的电子结构，即石墨烯-Au van der Waals（vdW）界面。色散校正的PBE-D2官能团用于描述声子光谱和结合能。从头算分子动力学模拟表明vdW框架一直保留到1200K 。在T = 1200 K以外，观察到准平面Au过渡到三维簇状结构。通过在石墨烯和Au导电板之间放置1-4个六方氮化硼（h-BN）单层来设计介电电容器。Au和石墨烯板之间的电荷分离是在垂直于石墨烯–h-BN–Au界面的外部场的作用下进行的。重量电容计算为C对于具有Au-石墨烯异质结构的h-BN双层，₁ = 7.6μF/ g，C ₂ = 3.2μF/ g。电容行为表现出与经典充电模型的强烈偏差，并说明了短接触时量子现象的重要性，该现象最终在较大的电极间距离处消失。石墨烯-Au界面预计将是一种令人兴奋的vdW异质结构，具有作为电介质电容器的潜在应用前景。