Theoretical Study of Electronic Properties of Functionalized Monolayers: Cu, Ag, Au, and Pt Atomic Wires on Graphene, h-BN Monolayer, Silicene, and Phosphorene

The structural and electronic properties of graphene, h-BN monolayer, silicene, and phosphorene monolayers functionalized with Cu, Ag, Au, and Pt atomic wires were investigated using van der Waals─corrected density functional theory. These atomic wires form stable, functionalized monolayers that exhibit physisorption on planar monolayers and chemisorption on nonplanar ones. This results in either linear or bent configurations of the atomic wires, depending on the interface strength, leading to distinct electronic states. A weaker interface induces metal-induced gap states near the Fermi level, whereas a stronger interface results in covalently hybridized states farther from the Fermi level. Analysis of the electron transport properties, calculated with a STM-like setup, shows a low tunneling barrier for the Pt wire and a high tunneling barrier for the Au wire across the series. Additionally, calculations show that Cu wire-functionalized graphene or h-BN monolayers exhibit a significantly high quantum capacitance at negative bias, suggesting strong capacity for hole storage. Overall, these findings highlight the importance of interface properties in determining the electronic properties of the functionalized monolayers. Furthermore, Pt wire-functionalized monolayers can act as low-resistance ohmic contacts due to their conductive interfaces. In contrast, Cu-functionalized graphene (h-BN monolayer) shows promise as a high-capacity anode material for energy storage applications.