Abstract
The diverse structural and electronic properties of the Si-adsorbed and -substituted monolayer graphene systems are studied by a complete theoretical framework under the first-principles calculations, including the adatom-diversified geometric structures, the Si- and C-dominated energy bands, the spatial charge densities, variations in the spatial charge densities and the atom- and orbital-projected density of states (DOSs). These critical physical quantities are unified together to display a distinct physical and chemical picture in the studying systems. Under the Si-adsorption and Si-substitution effects, the planar geometric structures are still remained mainly owing to the very strong C-C and Si-C bonds on the honeycomb lattices, respectively. The Si-adsorption cases can create free carriers, while the finite- or zero-gap semiconducting behaviors are revealed in various Si-substitution configurations. The developed theoretical framework can be fully generalized to other emergent layered materials. The Si-doped graphene systems might be a highly promising anode material in the lithium-ion battery owing to its rich potential properties.