Prediction of a Superhard Carbon-Rich C–N Compound Comparable to Diamond

摘要: Until now, it has been a challenge both in experiment and theory to design new superhard materials with high hardness values that are comparable of diamond. Here, by using first-principles calculations, we have introduced two phases for carbon-rich C–N compound stoichiometry C3N, which is predicted be energetically stable or metastable respect graphite solid N2 at ambient pressure. It found C3N layered structure containing graphitic layers sandwiched freely rotated molecules. The layer-structured calculated transform into three-dimensional C2221 9 GPa sp3-hybridized C atoms sp2-hybridized N atoms. Phonon dispersion elastic constant calculations reveal the dynamical mechanical stability phase Significantly, ideal strength indicate material an estimated Vickers (∼76 GPa) ...