Electronic, Structural, Optical, and Magnetic Characteristics A<sub>2</sub>MgS<sub>4</sub> of (A=Dy, Er) Spinel Sulfides: A Density Functional Theory Study
Mubashir Nazar, Nasarullah, Shatha A. Aldaghfag, Muhammad Yaseen, Muhammad Waqas, Mehwish Khalid Butt, Imed Boukhris
Abstract
Density functional theory (DFT) simulations are performed to explore the physical features of Dy 2 MgS 4 and Er 2 MgS 4 . Local density approximation with Hubbard potential (LDA + U) functional is utilized to examine the magnetic and electronic features. Half metallic ferromagnetic (HMF) behavior is confirmed by the spin‐resolved density of states (DOS) and band structure (BS) plots. Spin‐resolved BS and DOS show that Dy 2 MgS 4 and Er 2 MgS 4 for spin‐down are metallic, whereas both compounds in spin‐up show semiconductor nature with the bandgaps of 1.731 and 3.081 eV for Dy 2 MgS 4 and Er 2 MgS 4 , correspondingly. Both compounds also feature exchange energies and crystal field splitting, indicating the magnetic characteristics. The estimated magnetic moments of X 2 MgS 4 (X = Dy, Er) are 20 μ B and 12 μ B , correspondingly, also revealed by spin‐polarized magnetic density. Optical properties such as refractive index n ( ω ), absorption coefficient α ( ω ), dielectric constant , reflectivity R (, extinction coefficient k (ω), and optical conductivity σ ( ω ) are also explored. The optical bandgaps for MgX 2 S 4 (X = Dy, Er) are 1.70 and 1.51 eV, respectively; it shows that both are transparent to visible light. Results indicate that both materials can be suitable for spintronic and solar‐cell usage.