Group IV binary carbides with double layer honeycomb lattice structure

We explore the possibility of SiC, GeC, and SnC to form 2D structures, using evolutionary structure prediction tools and first-principles calculations. For SiC, a double layer honeycomb structure has the lowest energy, while GeC and SnC adopt other structures due to atomic size mismatch. The double layer honeycomb structure of SiC has a moderately large exfoliation energy, and covalent interlayer bonding that results in a stiff structure and high frequency phonons. Electronically, we find the double-layer SiC to be a semiconductor with an indirect bandgap in the visible spectral range. Finally, we explore stacked heterojunctions with graphene to illustrate how double layer SiC could be integrated with existing materials.