Transport properties of heavy-fermion systems

TL;DR

This paper models the temperature-dependent transport properties of heavy-fermion systems using dynamical mean-field theory, successfully reproducing experimental behaviors and revealing a strong-coupling Fermi-liquid fixed point.

Contribution

It applies dynamical mean-field theory with advanced impurity solvers to comprehensively analyze transport in heavy-fermion systems, highlighting a one-parameter scaling and Fermi-liquid behavior.

Findings

Reproduces experimental temperature dependence of resistivity and thermoelectric power.

Identifies a negative Seebeck coefficient at intermediate temperatures for large Coulomb interactions.

Suggests a universal scaling behavior linked to a Fermi-liquid fixed point.

Abstract

We calculate the temperature dependence of the transport properties of heavy-fermion systems such as resistivity, optical conductivity, thermoelectric power, the electronic part of the thermal conductivity, and the "figure of merit." The one-particle properties of the periodic Anderson model are obtained within dynamical mean-field theory for the paramagnetic phase using Wilson's numerical renormalization group and the modified perturbation theory as impurity solvers. We discuss the dependence of the transport properties on the band filling, valence, and Coulomb correlation $U$. The typical experimental findings can be reproduced and understood, in particular the temperature dependence of the resistance and the thermoelectric power and their absolute magnitude for both metallic heavy-fermion systems and Kondo insulators. For large values of $U$, we find a negative Seebeck coefficient $S(T)$ for an intermediate-temperature regime as observed in $S(T)$ of CeCu$_2$Si$_2$. We analyze different estimates for possible characteristic low-temperature scales of the lattice. Our results indicate a one-parameter scaling of thermodynamic and some transport properties with a strongly occupancy-dependent scaling function. This is consistent with a strong-coupling local Fermi-liquid fixed point of the effective site governing all low-lying excitations for $T\to 0$ in the paramagnetic phase.