A first-principles study on the phase stability of Mg_1-xFe_xN alloys: the unconventional rock-salt occurrence under high pressure

Due to the large atomic radius difference of Mg and Fe, alloys between them cannot be synthesized at ambient pressure. However, using a combination of high pressure and nitrogen incorporation, Serghiou et al [1] reported a rock-salt (RS) solid solution formation between MgN and FeN. The potential of these materials for applications in spintronics and their structural analog condition to Mg_1-xFe_xO, one of the most abundant phases of the Earth's interior, require knowledge of their properties. Therefore, we employ ab initio electronic structure calculations based on density functional theory (DFT) to investigate the field stability, structural and magnetic properties of bulk Mg_1-xFe_xN. Our results provide insights to understand the interplay between pressure and composition to stabilize the RS structure and the rise/suppression of magnetism in the solid solution.

[1] G. Serghiou, et al., Angew. Chem. Int. Ed. 54, 15109-15112 (2015).

M. Núñez Valdez is also at the Helmholtz-Zentrum Potsdam (GFZ).