Comparative study on the electronic and magnetic properties of two-dimensional Janus materials: h-SVSiN2 and t-SVSiN2

Search for two-dimensional magnetic semiconductors and half-metals are particularly significant for spintronic applications. By substituting N-Si-N atom group with S atoms on one side of SVSiN${}_2$ monolayer, two Janus monolayers: $h$-SVSiN${}_2$ and $t$-SVSiN${}_2$ were proposed. Through density functional theory, their electronic and magnetic properties have been studied systematically. Our results show that Janus $h$-SVSiN${}_2$ monolayer is an indirect semiconductor with intrinsic ferromagnetic order, while Janus $t$-SVSiN${}_2$ monolayer exhibits half-metallic feature. They both possess easy-plane magnetic anisotropy, with Curie temperature of 290 and 136 K for $h$-SVSiN${}_2$ and $t$-SVSiN${}_2$ monolayers, respectively. The electronic structures can be regulated by biaxial strain, such as semiconductor to half-metal transition. A spintronic device based on $t$-SVSiN${}_2$ monolayer has been designed, showing high magnetoresistance ratio and excellent spin filtering effect. These findings imply that Janus SVSiN${}_2$ monolayers are promising for 2D magnetism and spintronics.