First-Principles Study on the Half-Metallicity of New MXene Materials Nd(2)NT(2) (T = OH, O, S, F, Cl, and Br)

This work systematically studied the structure, magnetic and electronic properties of the MXene materials Nd(2)N and Nd(2)NT(2) (T = OH, O, S, F, Cl, and Br) via first-principles calculations based on density functional theory. Results showed that Nd(2)NT(2) (T = OH, O, S, F, Cl, and Br) have half-metallic characteristics whose half-metallic band gap width is higher than 1.70 eV. Its working function ranges from 1.83 to 6.50 eV. The effects of strain on its magnetic and electronic structures were evaluated. Results showed that the structure of Nd(2)NT(2) (T = OH, O, S, and Br) transitions from a ferromagnetic half-metallic semiconductor to a ferromagnetic metallic and ferromagnetic semiconductor under different strains. By contrast, the structures of Nd(2)NF(2) and Nd(2)NS(2) were observed to transition from a half-metallic semiconductor to a ferromagnetic metallic semiconductor under different strains. Calculations of the electronic properties of different proportions of the surface functional groups of Nd(2)NT( x ) (T = OH, O, and F; x = 0.5, 1(I, II), and 1.5) revealed that Nd(2)NO(1.5) has the characteristics of semiconductors, whereas Nd(2)NO(II) possesses the characteristics of half-metallic semiconductors. The other structures were observed to exhibit the characteristics of metallic semiconductors. Prediction of Nd(2)NT(2) (T = OH, O, S, F, Cl, and Br) increases the types of lanthanide MXene materials. They are appropriate candidate materials for preparing spintronic devices.