Paracyanogenlike Structures in High-Density Amorphous Carbon Nitride

Abstract

An ab initio based tight-binding molecular-dynamics method is used to generate 60 amorphous carbon nitride structures, $a$-CN, with various stoichiometries and densities, providing the first atomic level insight into the chemical bonding properties of these materials. Focusing on high densities, we observe clear trends counteracting the formation of a low-compressibility phase: (i) N incorporation strongly catalyzes C undercoordination, which in turn (ii) causes the nitrogens to develop paracyanogenlike (CN double and triple) bonding, and (iii) the most favorable densities for $a$-CN occur much lower than the desired hard crystalline ones.