Magnetization on nitrogen in extended honeycomb carbon layers from first principles: Case studies of CxN (x = 2, 6, 12)

Identification of unusual onset of spin polarization of N(p) states is reported. Full saturation up to 3μB (Bohr Magnetons) is demonstrated within extended two-dimensional carbon networks of CxN (x = 2, 6, 12) hexagonal structures refined based on density functional theory calculations. The cohesive energy is found to increase along the extension of the carbon network which opens perspective to experimental investigations through reactive deposition of thin films. From establishing the energy-volume equations of states of the two carbon rich nitrides done with assuming spin degenerate (non spin polarized) and spin-polarized configurations, the ground state is identified as ferromagnetic in both C6N and C12N. The electronic density of states plots show vanishing intensities at the Fermi level, whence the integer magnetizations. The variation of magnetization with volume points to strongly ferromagnetic behavior.