Engineering the electronic and magnetic properties of nitrogene monolayer and bilayer by doping: A first-principles study

The (N) nitrogen monolayer (nitrogene) has been predicted to be stable in the buckled hexagonal structure. However the non-magnetic nature and large band-gap may restrict its practical applications. In this paper, the electronic and magnetic properties of the nitrogene monolayer and bilayer doped with carbon (C) and boron (B) are investigated using first-principles calculations. Nitrogene monolayer is a non-magnetic two-dimensional (2D) material with an indirect band-gap of 4.185(6.023) eV determined by the PBE(HSE06) functional. Nitrogene bilayers with different stacking shaps are examined. Results reveal dynamical stability of the AA-, AA'-, and AB-stacked bilayers. Such atomic arrangements depict an energy gap reduction as compared to that of the monolayer. C doping causes strong spin polarization at the vicinities of the Fermi level, giving place to magnetic semiconductor nature. The magnetic properties are produced mainly by the C dopants (0.7 mu(B)), and also proximity induced small contributions on the N atoms (0.07 mu(B)). In contrast, B doping produces non-magnetic materials with band-gap red(u)ction (similar to 12% and 20.5%) for all considered systems. When the co-doping is treated, the effect on the electronic and magnetic properties can be considered as the combined effects of the separated C doping and B doping. Results presented herein may propose an efficient method to functionalize the nitrogene monolayer and bilayer for practical applications in optoelectronic and spintronic nano devices.