Metal-ceramic interfaces: Overlayer-induced reconstruction and magnetism of 4d transition-metal monolayers

Structural, electronic, and magnetic properties of metal-ceramic interfaces, M/MgO(001) (M=Pd, Rh, and Ru), have been investigated using the full potential linearized augmented-plane-wave method. Ru and Rh monolayers are found to be able to retain large spin magnetic moments on MgO(001) (1.95μB and 1.21μB for Ru and Rh, respectively)---indicating, in principle, the potential application of MgO(001) as a benign substrate for 4d monolayer magnetism. Significantly, according to our atomic-force determinations, the metal overlayers induce a sizable buckling reconstruction in the interfacial MgO layer, which enhances the M-MgO binding energy by 0.1 eV. The weak M-O interaction is mainly via tail effects; however, it affects the density of states at the Fermi level for Pd/MgO(001) significantly and completely eliminates the small magnetic moment of the free Pd monolayer (0.34μB)