Tuning the electronic and magnetic properties of MgO monolayer by nonmetal doping: A first-principles investigation

Interestingly, significant magnetization of two-dimensional (2D) materials may be induced by doping with nonmetal species. In this work, the structural, electronic, and magnetic properties of pristine and N-, C-, and B-doped graphene-like MgO monolayer have been studied using first-principles calculations. MgO single layer becomes 2D ferromagnetic (FM) semiconductor when substituting one O atom by one N, C, or B atom. Upon increasing doping level, the electronic structure and magnetic properties show a strong dependence on the separation of dopants. The 2N-doped systems exhibit antiferromagnetic (AFM) coupling. The C2 and B2 dimers are formed when replacing two neighboring O atoms, giving place to a non-magnetic semiconductor behavior. However, when these are further apart, significant magnetism is induced due to the long-term effects. Specifically, 2C-doped structure undergoes a FM-AFM-FM-AFM state transition, whereas AFM state is found to be energetically stable for the 2B-doped systems. In all cases, magnetic properties are produced mainly by the dopants, meanwhile the contribution from remaining constituent atoms is quite small. This study suggests an effective approach to tune the electronic and magnetic properties of pristine and doped MgO monolayer by simply controlling the dopant concentration and distance between dopants, which may be helpful for the applications in optoelectronic and spintronic nanodevices.