Graphene/ MoS2 heterostructures as templates for growing two-dimensional metals: Predictions from ab initio calculations

Abstract

Preparation of single-atom-thick layers of ordinary metals has been a challenging task since their closely packed atoms lack layered structure with highly anisotropic bonding. Using computational modeling based on density functional theory we showed that graphene/${\mathrm{MoS}}_{2}$ heterostructures can be used as suitable templates to grow stable two-dimensional (2D) clusters, as well as extended monoatomic layers of metals with nonlayered structure in the bulk. Considering gold and lithium as two metals with markedly different properties, we found that Li intercalants strengthen coupling between graphene (G) and ${\mathrm{MoS}}_{2}$, mainly due to electrostatic attraction of 2D materials with positively charged Li atoms. However, intercalation with large Au atoms gives rise to a significant increase in the distance between G and ${\mathrm{MoS}}_{2}$ and thus, weakens their interaction. In addition to strong preference for 2D growth, we demonstrated that Au intercalants weakly interact with both G and ${\mathrm{MoS}}_{2}$, and hence $\mathrm{G}/{\mathrm{MoS}}_{2}$ vertical heterostructures could be a promising framework to prepare gold 2D structures with electronic properties closely resembling those of the hypothetical free-standing hexagonal gold monolayer.