The theoretical framework, which is built from the first-principles results, is successfully developed for investigating emergent two-dimensional materials, as it is clearly illustrated by carbon substitution in silicene. By the delicate VASP calculations and analyses, the multi-orbital hybridizations are thoroughly identified from the optimal honeycomb lattices, the atom-dominated energy spectra, the spatial charge density distributions, and the atom and orbital-decomposed van Hove singularities, being very sensitive to the concentration and arrangements of guest atoms. All the binary two-dimensional silicon-carbon compounds belong to the finite- or zero-gap semiconductors, corresponding to the thoroughly/strongly/slightly modified Dirac-cone structures near the Fermi level. Additionally, there are frequent π and σ band crossings, but less anti-crossing behaviors. Apparently, our results indicate the well-defined π and σ bondings.
Six-fold symmetry origin of Dirac cone formation in two-dimensional materials
