Cubic gauche-CN: A superhard metallic compound predicted via first-principles calculations

In this paper, we suggest a novel potential superhard material, a new carbon nitride phase consisted of sp3 hybridized bonds, possessing a cubic P213 symmetry (8 atoms/cell, labeled by cg-CN) which is similar to cubic gauche nitrogen (cg-N) by first-principles calculations. It is a metallic compound, while most of other superhard materials are insulators or semiconductors. The Vickers hardness of cg-CN is 82.56 GPa, and if we considered the...