Transition Metal-Doped Tin Monoxide Monolayer: A First-Principles Study

Using first-principles calculations, the structural and electronic properties of monolayer SnO doped with 3d transition metals from V to Ni were investigated. The results indicate that the substitutional doping is preferred under oxygen-rich conditions for all transition metals. In addition, all dopants induce magnetism by forming TMsub except for Ni. Such a magnetic behavior is due to the interaction between the dopants and the surrounding Sn/O atoms. The stability and the origin of magnetism are investigated by considering different defect complexes. The results show that a defect complex composed of substitutional dopants and oxygen vacancies has the same magnetic moment as that of substitutional dopants of TMsub alone, whereas the magnetic moments of defect complexes composed of ubsubstitutional, TMsub, and tin vacancy, V-Sn, vary significantly. The moments of defect complexes, such as (Co-sub + V-Sn) and (Ni-sub + V-Sn), are enhanced compared to those of the substitutional alone. On the other hand, the magnetic moments of (Fe-sub + V-Sn) and (Mn-sub + V-Sn) are the same as those of substitutional dopants alone, whereas (Cr-sub + V-Sn) and (V-sub + V-Sn) have lower magnetic moments than single TMsub.