Structural and Electronic Properties, and Pressure-Induced Phase Transition of Layered C₅N: a First-Principles Investigation

Seven layered C₅N configurations constructed from hexagonal BN and graphite structures are studied using an ab initio pseudopotential density functional method. The structural and electronic properties, and pressure−induced phase transition are investigated by calculating the total energy, structural parameter, formation energy, elastic constant, band structure and electron density of state. The results show that the three C₅N configurations constructed from the h−BN structure are more stable energetically than those four configurations from graphite structure. The C₅N−I configuration with the highest symmetry and the AA stacking sequence along the c−axis is the most stable. This structure is stable mechanically and its phase separation is difficult. The C₅N phase is expected to have a metallic character. A critical pressure of about 20 GPa is predicted for the synthesis of a monoclinic C₅N phase from the layered C₅N phase.