Electronic and magnetic properties tuning of armchair BC2N nanoribbons by edge modification

By first-principles calculations, we study the edge effects on the armchair BC2N nanoribbons (ABC2NNRs) with six kinds of foreign atoms (i.e., H, F, O, Cl, S, and Se). Physically, atoms (Cl, S, and Se) with large radius can only passivate half of the edge due to the Coulomb repulsion effect, and its functional site is selective. We find the atom species can significantly tune the electronic and magnetic properties of the ABC2NNRs. Depending on the edge alignment and the magnetic state, we get half-metals, spin-polarized metals, nonmagnetic semi-metals, and nonmagnetic metals. Interestingly, nonmagnetic metals would transit to semiconductors by slightly doping.