Spin-Polarization and Resonant States in Electronic Conduction through a Correlated Magnetic Layer

The transmission through a magnetic layer of correlated electrons sandwiched between noninteracting normal-metal leads is studied within model calculations. The linear regime in the framework of the Meir-Wingreen formalism is considered, according to which the transmission can be interpreted as the overlap of the spectral function of the surface layer of the leads with that of the central region. By analyzing these spectral functions, it is shown that a change in the coupling parameter between the leads and the central region significantly and nontrivially affects the conductance. The role of band structure effects for the transmission is clarified. For a strong coupling between the leads and the central layer, high-intensity localized states are formed outside the overlapping bands, while for weaker coupling this high-intensity spectral weight is formed within the leads' continuum band around the Fermi energy. A local Coulomb interaction in the central region modifies the high-intensity states, and therefore the transmission. For the present setup, the major effect of the local interaction consists in shifts of the band structure because any sharp features are weakened due to the macroscopic extension of the layers.