Interior edges induced half-metallic ferromagnetism in graphitic carbon nitride structures

We study the magnetic properties of graphitic carbon nitride, g-C4N3. A microscopic tight-binding model incorporated with the Hatree mean-field approach is adopted, showing that the g-C4N3 exhibits the significant ferromagnetism induced from the edge states. These edge states appearing on the zigzag boundaries not only ffdeorm the flat band but also upon proper hole doping provide the electrons with single polarized spin exciting to the Dirac linear bands and causes g-C4N3 half-metallic. The half-metallicity survives at room temperature and does not require strong Coulomb repulsion for induction. The ferromagnetism of these states yielding the half-metallicity refers to the broken or imperfectness of the honeycomb lattice structure; specifically, the ferromagnetic states are formed on the zigzag boundaries surrounding the vacancies in the imperfect (some lattice points being missed or removed) honeycomb lattice. We thus indicate that the half-metallicity should be generally reachable in materials of this kind of structure.