Electronic structure of single-layer superlattices (GeC)$_{1}$(SiC)$_{1}$, (SnC)$_{1}$(SiC)$_{1}$, and (SnC)$_{1}$(GeC)$_{1}$

The crystal and electronic structures of GeC, SiC, and SnC crystals and superlattices based on them, GeC/SiC, SnC/SiC, and SnC/GeC, are modeled within density functional theory. The equilibrium lattice constants are obtained, the band spectra and densities of states are calculated, and the specific features of the formation of the valence band and chemical bonding in these crystals and superlattices are studied.