Configuration-dependent magnetism from two manganese atoms on Cu(001)

Our calculations, based on first principles, have shown that magnetism from two manganese atoms embedded in the surface layer of Cu(001) depends on their relative positions. If the two Mn atoms are nearest neighbors, the magnetic moment for either atom is only 0.49/μB. If separated by one lattice constant, each of the two Mn atoms has a larger moment of 0.66/μB and the surrounding Cu atoms also acquire substantial moments. Finally, when a Cu atom is interposed between the two Mn atoms, moment for each Mn atom increases to 3.71/μB, about the value of a single Mn impurity in the surface layer. The results indicate that a strong d-d interaction between the Mn and Cu atoms and a weaker interaction between the Mn atoms are behind the shifting of energy levels for the majority and minority spins, which in turn results in very different magnetic moments.