  Since the rising of graphene, boron nitride monolayers have been deeply
studied due to their structural similarity with the former. A hexagonal
graphene-like boron-carbon-nitrogen (h-BCN) monolayer was synthesized recently
using bis-BN cyclohexane (B2N2C2H12) as a precursor molecule. Herein, we
investigated the electronic and structural properties of this novel BCN
material, in the presence of single-atom (boron, carbon, or nitrogen)
vacancies, by employing density functional theory calculations. The stability
of these vacancy-endowed structures is verified from cohesion energy
calculations. Results showed that a carbon atom vacancy strongly distorts the
lattice leading to breaking on its planarity and bond reconstructions. The
single-atom vacancies induce the appearance of flat midgap states. A
significant degree of charge localization takes place in the vicinity of these
defects. It was observed a spontaneous magnetization only for the boron-vacancy
case, with a magnetic dipole moment about 0.87 mu_B. Our calculations predicted
a direct electronic bandgap value of about 1.14 eV, which is in good agreement
with the experimental one. Importantly, this bandgap value is intermediate
between gapless graphene and insulating h-BN.
