Electronic Structures of BC₂N Nanoribbons

We reveal a rich variety of electronic and magnetic properties of H-terminated BC 2 N nanoribbons (BC 2 NNRs) by using extensive first-principles calculations. Zigzag edged BC 2 NNRs ( z -BC 2 NNRs) can be semiconducting or metallic depending on the alignment of edge atoms. In particular, magnetic and even half-metallic behaviors can appear in some edged z -BC 2 NNRs when the ribbon width is over a critical value. Armchair-edged BC 2 NNRs also can be semiconducting or metallic but determined by the proportion of carbon, nitrogen, and boron atoms in the ribbons. The band gaps of all semiconducting BC 2 NNRs can be explained by a universal mechanism that is due to the charge polarization between the opposite edges, which is impaired with increasing ribbon width.