The existence of single-layer diamond or diamane, which could adopt the properties of its bulk counterpart, has been verified by previous calculations and experiments. Even though, carbon atoms on the top and bottom surfaces need to form dangling bonds with atoms and/or molecules to stabilize their ${\mathrm{sp}}^3$ hybridization. In this paper, diamane is substituted by N atoms assisting the diamondlike structure to be stabilize without any passivation studied by ab initio calculation. One-fourth of N substitution on diamane, vertically stacking as NCCC, is found to be stable by surface reconstruction forming a Pandey $\pi$-chain structure and has an antiferromagnetic property. Half nitrogen substitution on diamane, vertically stacking as NCCN, can be stable and prevails the diamane form. Its elastic constants yield high values, for example, its $C_{11}$ is as twice as diamond and its $C_{33}$ is only 21% lower than diamond. The NCCN phase is a metastable phase at 10 GPa compared with other layered carbon nitride phases showing the possible pathway to be created.

• Received 12 April 2020
• Revised 20 July 2020
• Accepted 21 July 2020

DOI:https://doi.org/10.1103/PhysRevB.102.075418