Periodic Anderson model with correlated conduction electrons

Abstract

We investigate a periodic Anderson model with interacting conduction electrons which are described by a Hubbard-type interaction of strength Uc. Within dynamical mean-field theory the total Hamiltonian is mapped onto an impurity model, which is solved by an extended non-crossing approximation. We consider the particle-hole symmetric case at half-filling. Similar to the case Uc = 0, the low-energy behavior of the conduction electrons at high temperatures is essentially unaffected by the f electrons and for small Uc a quasiparticle peak corresponding to the Hubbard model evolves first. These quasiparticles screen the f moments when the temperature is reduced further, and the system turns into an insulator with a tiny gap and flat bands. The formation of the quasiparticle peak is impeded by increasing either Uc or the c-f hybridization. Nevertheless almost dispersionless bands emerge at low temperature with an increased gap, even in the case of initially insulating host electrons. The size of the gap in the one-particle spectral density at low temperatures provides an estimate for the low-energy scale and increases as Uc increases. 71.27.+a,75.20.Hr,71.10.Fd

Orbital-selective Mott transition in multiband systems: Slave-spin representation and dynamical mean-field theory

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