Structural stability and the electronic and magnetic properties of ferrimagnetic Mn4N(0Â 0Â 1) surfaces

We have carried out spin-polarized first principles calculations to describe the surface stability and the electronic and magnetic properties of Mn4N(0 0 1) surfaces. Results show two different surface terminations with different N content. The surface formation energies indicate that for manganese rich conditions the most stable structure is a MnN terminated surface. Whereas, from intermediate to nitrogen rich conditions, a MnN terminated surface with excess of nitrogen atoms is the most favorable. The stability of these surfaces can be traced to the formation of Mn-N bonds at the surface. The stable surfaces are Ferrimagnetic along the direction perpendicular to the surface, retaining a bulk-like behavior. However, there is a decrease in the Mn magnetic moments due to the presence of the surface. Density of states shows an asymmetric behavior, inherent of a Ferrimagnetic state. Finally, the surfaces are metallic with the main contributions around the Fermi level coming from the Mn-d orbitals. The knowledge about the atomic arrangements of the Mn4N surfaces may serve to explain and understand the formation of more complex and technologically applicable ferromagnetic/ferrimagnetic and antiferromagnetic/ferrimagnetic heterostructures.