Substitutional transition metal doping in MoSi₂N₄ monolayer: structural, electronic and magnetic properties

Monolayer MoSi₂N₄ (MoSiN) was successfully synthesized last year [Hong et al., Science369, 670 (2020)]. The MoSiN monolayer exhibited semiconducting characteristics and exceptional ambient stability, calling for more studies of its properties. Here, we conduct first-principle calculations to examine the structural, magnetic, and electronic properties of substitutional doping of MoSiN monolayers with transition metals (TM) at the Mo site (TM-MoSiN). We find that the Sc-, Y-, Ti-, and Zr-MoSiN are metallic systems, while Mn-, Tc-, and Ru-MoSiN are n-type conducting. The Fe-MoSiN is a dilute magnetic semiconductor, and the Ni-MoSiN is a metal (or half-metal). The inclusion of spin-orbit coupling turns them into a half-metal and a semimetal, respectively. We also find that the work function of TM-MoSiN and the bond lengths between the TM and neighbor atoms increase as the atomic radius and electronegativity of the TM atom increase, respectively. The Fe-, Co-, and Ni-MoSiN may be used in spintronic devices, while Mn-, Rh- and Pd-MoSiN could be utilized for spin filter applications.