Relative stability of some possible phases of graphitic carbon nitride

Abstract

Various graphitic phases of ${\mathrm{C}}_3{\mathrm{N}}_4$ are examined using the local-density approximation plane-wave-pseudopotential approach. These are three forms of p graphite and the $P6\mathrm{}¯m2\mathrm{}$ graphite structure. Each differs only in planar stacking and character of planar C-N bonds. Two forms of p graphite are predicted to be stable with energies very close to the $P6\mathrm{}¯m2\mathrm{}$ structure. This suggests a strong phase instability of the graphite structures and material softening along the c axis.