Boron and carbon in two-dimensional nitrogene structures: Heterodoping, doping, and chemical functionalization

Abstract

We perform density functional calculations to determine the effects of simultaneous doping with carbon (C) and boron (B) on the electronic properties of nitrogene. Our procedure substitutionally incorporates the two dopants into the nitrogen monolayer. We analyze the relative position between dopants by considering different configurations. Band structure, density of states, band gaps, magnetic stability energies (energy difference between states with total magnetization with spin S=1 and S=0), and energetic stability were examined. The codoped structures exhibit a spin−dependent band gap with a strength of 1.04–2.68 eV, which is reduced compared to that in nitrogene (3.80 eV). The B-C codoped nitrogene incorporated ferromagnetism with well-localized flat bands around the Fermi level. A spin−polarized ground state was exhibited by the systems with a total magnetization of S=1, in which magnetic moments were localized mainly at the C atom and its first neighbors. The systems displayed an antiferromagnetic ordering when the total spin was fixed to S=0. The valence band maximum (VBM) was dominated by spin−up, while the conduction band minimum (CBM) was dominated by spin−down. Dopants placed as second neighbors in the nitrogene structures exhibited the most prominent band gap and magnetic stability.