The Impact of Nb Doping on Structural, Electronic, Magnetic and Optical Properties of Monolayer Mgo:DFT Study

The effects of niobium (Nb) doping on the structural, electronic, magnetic, and optical properties of monolayer (ML) magnesium oxide (MgO) are investigated using spin‐polarized density functional theory (DFT). Defect formation energy caculations reveal that doping Nb on the Mg site is energetically favorable. Structural analysis shows that Nb doping increases in all structural parameters, attributed to the larger atomic radius of Nb compared to Mg. Electronic band structure calculations indicate a reduction in the bandgap of ML MgO, from 3.44 to 3.39 eV and 3.0 eV for 6.25% and 12.5% Nb doping, respectively. The total density of states and band structure analysis suggests a transition from paramagnetic to ferromagnetic behavior, along with a shift toward half‐metallic properties with Nb doping. Notably, using mean‐field theory in combination with spin‐polarized DFT, the ferromagnetic transition temperature (T) for 12.5% Nb‐doped MgO is predicted to be 346 K. Furthermore, optical absorption studies reveal a significant enhancement in the absorption coefficient, particularly in the visible spectrum, due to Nb doping. These findings highlight the potential of Nb‐doped MgO for applications in spintronics and optoelectronics, although further experimental validation is required to confirm these theoretical predictions.