Electronic, rashba and photocatalytic properties of janus XMoYZ2 (X= S, Se, Te ; Y=Si, Ge and Z=N, P) monolayers

In this work, the electronic, photocatalytic, and spin properties of 2D Janus XMoYZ${}_2$ (X= S, Se, Te; Y=Si, Ge and Z=N, P) monolayers are studied. The electronic properties are investigated and the results indicate that all of them are semiconductor with a suitable bandgap. The band structures with spin–orbit consideration indicate Rashba spin-splitting at the $\Gamma$-valley in the valence band. The spin-splitting at the K-point in the valence band is also significant, whereas the conduction band has negligible spin-splitting. Due to the mirror asymmetry of these compounds, their potential distribution and the corresponding dipole moments are investigated. Finally, by studying the photocatalytic properties, it is found that the redox happened on both sides of SMoSiN${}_2$ and SMoGeN${}_2$ monolayers. However, in the cases of SMoSiP${}_2$ and TeMoGeN${}_2$ monolayers, each photocatalytic half-reaction occurs on one side where the generated hydrogen and oxygen molecules are separated.