Magnetic and structural properties of Mn adatoms on copper nitride over Cu(100)

Abstract

Magnetic and structural properties of Mn adatoms and dimers adsorbed on a single atomic layer of copper nitride $({\text{Cu}}_{3}\text{N})$ over a Cu(100) substrate are explored by first-principles calculations based on the density-functional theory. In all cases investigated here, the adsorption of the Mn atoms and dimers causes significant local structural changes and charge transfer between the ions, in comparison with the clean surface. However, some important properties depend strongly on Mn atoms and dimers local environments. When Mn atoms of the dimer are positioned atop N atoms, the direct coupling between the Mn atoms is antiferromagnetic. On the other hand, when the Mn atoms are positioned atop Cu atoms, which is the energetically favorable configuration, the antiferromagnetic coupling connecting the Mn spins has a superexchange character which is established through the N anions laying between them.