First-principles study of the effect of single atom adsorption on the structure, electronic and magnetic properties of MoSi ₂ N ₄

In order to study the effective methods to adjust the electronic and magnetic properties of monolayer MoSi₂N₄, the effects of non-metallic atom (B, C, N, O, F) adsorption and metal atom (Fe, Co, Mn) adsorption on the electronic and magnetic properties of monolayer MoSi₂N₄has been investigated, using first-principles density functional theory within the generalized gradient approximation. The results show that the adsorption of O is more stable than that of other atoms. The interaction between Mn and MoSi₂N₄is the weakest. The adsorption of these atoms reduces the band gap of monolayer MoSi₂N₄. The decrease of the band gap is the most obvious for Co and B atoms, whose band gap is close to zero. The adsorption of O atom has the least impact on the energy band. After the adsorption of N atom and metal atoms, the systems are still indirect band gap semiconductors. Another atom adsorption can induce the material undergoes an indirect to direct band gap transition. In addition to O and F adsorption, the adsorption of other atoms can not only adjust the band gap, but also change the magnetic properties of monolayer MoSi₂N₄. The magnetic moment of monolayer MoSi₂N₄after adsorption of B, C and N is basically concentrated around the adsorbed atoms and their neighboring atoms. The magnetic moment of metal atom adsorption is more concentrated on the adsorbed atoms, especially in the structure of Mo adsorption, and the contribution of other atoms to the magnetic moment is minimal.