A first-principles study of nitrogene with monovacancy and light-atom substituted doping

Recent studies have shown that group V monolayer, called nitrogene, remain stable in a free-standing buckled honeycomb structure with a two-dimensional hexagonal lattice. It is predicted to be a nonmagnetic, wide band gap semiconductor. In this paper, three allotropes of nitrogen single layers are firstly investigated and it is determined that the buckled honeycomb structure of nitrogene (denoted as b-N) is the lowest energetically. Then taking b-N as an example, the geometrical structures and the electronic properties of it with monovacancy and substituted doping with heterogeneous atoms, such as B, C, O, Al, Si, and P, are studied. It is found that the single vacancy in b-N is in P_3m symmetry and it is polarized stable with a local magnetic moment of 3.0 μ _B for each monovacancy. The substituted heterogeneous atom has little impact on the geometrical structures, while for Al, Si, and P, they move upward of the nitrogene plane due to the larger atomic radius compared to N. It is also found that C-, Si-, and O-doped nitrogene are spin-polarized stable, bringing a magnetic moment of about 1.0 μ _B for each doped atom. Doping of multiple carbon atoms in one hexagonal ring of nitrogene, which prefers forming the polymer and the nitrogene with the doping of an odd number of carbon atoms, is magnetic stable, arising about 1.0 μ _B magnetic moment in each supercell. (paper)