First-principles study of magnetism of 3d transition metals and nitrogen co-doped monolayer MoS₂

The electronic structures and magnetic properties of diverse transition metal (TM=Fe, Co, and Ni) and nitrogen (N) co-doped monolayer MoS₂ are investigated by using density functional theory. The results show that the intrinsic MoS₂ does not have magnetism initially, but doped with TM (TM=Fe, Co, and Ni) the MoS₂ possesses an obvious magnetism distinctly. The magnetic moment mainly comes from unpaired Mo:4d orbitals and the d orbitals of the dopants, as well as the S:3p states. However, the doping system exhibits certain half-metallic properties, so we select N atoms in the V family as a dopant to adjust its half-metal characteristics. The results show that the (Fe, N) co-doped MoS₂ can be a satisfactory material for applications in spintronic devices. On this basis, the most stable geometry of the (2Fe-N) co-doped MoS₂ system is determined by considering the different configurations of the positions of the two Fe atoms. It is found that the ferromagnetic mechanism of the (2Fe-N) co-doped MoS₂ system is caused by the bond spin polarization mechanism of the Fe-Mo-Fe coupling chain. Our results verify that the (Fe, N) co-doped single-layer MoS₂ has the conditions required to become a dilute magnetic semiconductor.