A first-principles study of the effects of atom impurities, defects, strain, electric field and layer thickness on the electronic and magnetic properties of the C₂N nanosheet

Using the first-principles calculations, we explore the structural and novel electronic/optical properties of the C₂N nanosheet. To this goal, we systematically investigate the affect of layer thickness, electrical field and strain on the electronic properties of the C₂N nanosheet. By increasing the thickness of C₂N, we observed that the band gap decreases. Moreover, by applying an electrical field to bilayer C₂N, the band gap decreases and a semiconductor-to-metal transition can occur. Our results also confirm that uniaxial and biaxial strain can effectively alter the band gap of C₂N monolayer. Furthermore, we show that the electronic and magnetic properties of C₂N can be modified by the adsorption and substitution of various atoms. Depending on the species of embedded atoms, they may induce semiconductor (O, C, Si and Be), metal (S, N, P, Na, K, Mg and Ca), dilute-magnetic semiconductor (H, F, B), or ferro-magnetic-metal (Cl, Li) character in C₂N monolayer. It was also found that the inclusion of hydrogen or oxygen impurities and nitrogen vacancies, can induce magnetism in the C₂N monolayer. These extensive calculations can be useful to guide future studies to modify the electronic/optical properties of two-dimensional materials.