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.