Group IV binary carbides with double layer honeycomb lattice structure

Abstract

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.