We study the non-Fermi liquid behavior in a two-band extended Hubbard model. In the limit of infinite dimensions, where only local correlations are taken into account, this model in the mixed-valence regime is known to display a metallic non-Fermi liquid phase with spin-charge separation. Here we address the effect of intersite RKKY-like interactions using an extended dynamical mean-field approach. We find that the spin-charge separation survives the quantum fluctuations associated with the intersite density-density and spin-exchange interactions. We determine the spin, charge, and single-particle correlation functions in the non-Fermi liquid state.We study the non-Fermi liquid behavior in a two-band extended Hubbard model. In the limit of infinite dimensions, where only local correlations are taken into account, this model in the mixed-valence regime is known to display a metallic non-Fermi liquid phase with spin-charge separation. Here we address the effect of intersite RKKY-like interactions using an extended dynamical mean-field approach. We find that the spin-charge separation survives the quantum fluctuations associated with the intersite density-density and spin-exchange interactions. We determine the spin, charge, and single-particle correlation functions in the non-Fermi liquid state.

Europhysics Letters (EPL)Jan 15, 199974 citations

Fermi-liquid versus non-Fermi-liquid behavior in a two-band model of high-temperature superconductivity

Claudio Castellani, Gabriel Kotliar

We solve an extended Hubbard model describing a system with two $N$ -fold degenerate bands in the limit $N=\ensuremath{\infty}$. The system exhibits a phase transition from Fermi liquid to non-Fermi liquid as the exchange interaction becomes comparable with the hybridization energy.We solve an extended Hubbard model describing a system with two $N$-fold degenerate bands in the limit $N=\ensuremath{\infty}$. The system exhibits a phase transition from Fermi liquid to non-Fermi liquid as the exchange interaction becomes comparable with the hybridization energy.

Physical review. B, Condensed matterFeb 1, 198915 citations

We solve an extended Hubbard model describing a system with two

N

-fold degenerate bands in the limit $N=\ensuremath{\infty}$. The system exhibits a phase transition from Fermi liquid to non-Fermi liquid as the exchange interaction becomes comparable with the hybridization energy.