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 TM_sub 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 TM_sub alone, whereas the magnetic moments of defect complexes composed of ubsubstitutional, TM_sub, 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 TM_sub.