Electronic structure and magnetism of the Cu/Ni{100} interface: Self-consistent local-orbital calculations

Abstract

The spin-polarized electronic structure of $p(1\ifmmode\times\else\texttimes\fi{}1)\mathrm{Cu}$ on both sides of a three-layer Ni{100} slab has been calculated using the self-consistent local-orbital method. The Ni layer adjacent to the Cu overlayer has its magnetic moment reduced to $0.37{\ensuremath{\mu}}_{B}$ compared with the bulklike center-plane moment $0.55{\ensuremath{\mu}}_{B}$. The Cu adlayer is essentially unpolarized. We attribute the interface-moment reduction to $\mathrm{sp}\ensuremath{-}d$ charge transfer and hybridization of Cu $\mathrm{sp}$ and Ni $d$ levels. The $d$-electron number is 8.91 at the interface, while the central-plane value is 8.74, just as we found earlier for five-layer Ni{100}. All layers are nearly charge neutral. Our results for the magnetic moments agree well with those of Tersoff and Falicov, who did not allow for $\mathrm{sp}\ensuremath{-}d$ charge-transfer effects. Adsorbate bands are presented which should be observable in angle-resolved photoemission spectroscopy. These bands may be described as Cu-monolayer bands, shifted and broadened by interaction with the Ni substrate.