Half-metallic ferromagnetic properties of Mn-doped MoSe<sub>2</sub> and its heterostructure

Abstract

<p indent="0mm">We use the first-principle method to investigate the crystal structure, electronic structure, and magnetic properties of a Mn-doped MoSe₂ monolayer (Mo_0.75Mn_0.25Se₂). The spin-up electrons exhibit metallic properties, whereas the spin-down electrons exhibit insulating properties, indicating the half-metallic properties of Mo_0.75Mn_0.25Se₂. The density of states shows a strong coupling between dopant Mn 3d orbitals via the Mo 4d and Se 4p states. We investigate the dispersion relation of the spin-spiral energy <italic>E</italic>(<bold>q</bold>) and the wave vector <bold>q</bold> for Mo_0.75Mn_0.25Se₂ under the generalized Bloch condition. The exchange coupling coefficient<italic> J</italic>_{<italic>i</italic>} (<italic>i</italic> = 1, 2, 3, and 4) is obtained using the Heisenberg interaction model. The next-nearest-neighbor interaction exchange coupling coefficient <italic>J</italic>₂ is non-negligible, although the first nearest neighbor, <italic>J</italic>₁, plays the most important role in the interaction between atoms. Because Mo_0.75Mn_0.25Se₂ is a two-dimensional (2D) metal material that can easily undergo oxidation, we use insulating MoSe₂ to fabricate a MoSe₂/Mo_0.75Mn_0.25Se₂/MoSe₂ heterostructure. First-principle calculations results show that the half-metallic ferromagnetic properties of Mo_0.75Mn_0.25Se₂ can be protected very well in the heterostructure. The findings of this study can promote the understanding of the mechanism of 2D half-metallic ferromagnetic properties and provide a general method for designing materials that show such properties with stability.