Understanding the stability of Fe incorporation within Mn3N2(001) surfaces: An ab-initio study

We present first principles spin-polarized calculations of the adsorption and incorporation of iron in the Mn3N2(001) surfaces. By means of a surface formation energy criterion, it is demonstrated that Fe incorporation is energetically stable for all studied surfaces. An Fe bilayer formation is achieved after Fe atoms displace Mn atoms in the sub-surface N-vacancy layers. An analysis of the magnetic coupling shows an antiferromagnetic alignment along the [0 0 1] direction as in the clean, ideal surfaces. Also, the in-plane magnetic coupling between Fe-Fe and Fe-Mn shows a ferromagnetic tendency, similar to the clean, ideally terminated surfaces. These results clearly indicate that Fe behaves like Mn when adsorbed into the Mn3N2 surface. Density of states calculations of the stable structures show a slight deviation from the antiferromagnetic-like behavior, with the most important contribution around the Fermi level coming from the Fe-d and Mn-d orbitals. (C) 2015 Elsevier B.V. All rights reserved.