Re-examining the giant magnetization density in α′′-Fe16N2 with the SCAN+U method. Issue 29 (19th July 2022) - Devi, Assa Aravindh Sasikala
Abstract : The optimized structure of α′′-Fe16 N2 with the three different Fe sites marked distinctly. Abstract : We present an in-depth discussion of the magnetic ground state of α′′-Fe16 N2 within the framework of the density functional theory (DFT). The exchange–correlation effects are treated using a variety of schemes, including the local-spin-density approximation, the generalized-gradient approximation, and the Strongly-Constrained-and-Appropriately-Normed (SCAN) scheme. We also delineate effects of adding an on-site interaction parameter U on the Fe sites. Among all the schemes considered, only SCAN+ U is found to capture the surprisingly large magnetization density in α′′-Fe16 N2 that has been observed experimentally. Our study shows how the combination of SCAN and self-interaction corrections applied on different Fe sites through the parameter U can reproduce both the correct equilibrium volume and the giant magnetization density of α′′-Fe16 N2 .