Effect of Hubbard <i>U</i> on calculations of magnetic properties of α″–Fe₁₆N₂

The ordered iron nitride phase α″–Fe16N2 has been a potential candidate for rare-earth free magnets with giant saturation magnetization, but first-principles electronic-structure calculations have struggled to reproduce recent observations of high magnetic moment, while magnetocrystalline anisotropy (MCA) vary significantly. Within the framework density-functional theory (DFT), common extension usual generalized-gradient approximation (GGA) exchange-correlation (XC) functional is inclusion Hubbard parameters U (,J) as GGA + U. A number previous papers applied this method Fe16N2, each their own choice parameters. plane-wave DFT code Quantum ESPRESSO was employed more comprehensively study effect value and J on system, particularly respect its properties. Various approaches setting were compared, including self-consistent via linear-response method.