Crystal Structure and Electronic Properties of Graphite-Like C7N Phase from First-Principles Calculations

Abstract

The structural and electronic properties of graphite-like C7N compound have been calculated by using first-principles pseudopotential density functional method for ten possible C7N configurations, which are deduced from graphite and hexagonal boron nitride unit cell. The calculated total energy results show that the configuration C7N-I with AA stacking sequence along the c-axis based on hexagonal BN structure has been shown to be the most stable structure. From the calculated electronic band structures and electron density of states, the monolayer and bulk phase of C7N are expected to show insulating and metal states, respectively. The graphite-like C7N phases have been predicted to be a stable phase at ambient conditions by formation energy and elastic constant calculations. A critical pressure of about 41 GPa is expected for a synthesis of cubic C7N phase from this graphite-like C7N.