Low energy scales of Kondo lattices: mean-field perspective

TL;DR

This paper reviews the low temperature properties of Kondo lattice systems using mean-field theory, focusing on the energy scales T_K and T_0 and their dependence on various parameters, including magnetic field and intersite interactions.

Contribution

It provides a mean-field analysis of the characteristic energy scales in Kondo lattices, highlighting conditions for Kondo breakdown and effects of magnetic correlations.

Findings

T_K and T_0 depend on electronic filling and density of states.

External magnetic fields can cause Kondo breakdown by vanishing energy scales.

Adding superexchange mimics intersite magnetic correlations affecting Kondo physics.

Abstract

A review of the low temperature properties of Kondo lattice systems is presented within the mean-field approximation, focusing on the different characteristic energy scales. The Kondo temperature, T_K, and the Fermi liquid coherence energy, T_0, are analyzed as functions of the electronic filling, the shape of the non-interacting density of states, and the concentration of magnetic moments. These two scales can vanish, corresponding to a breakdown of the Kondo effect when an external magnetic field is applied. The Kondo breakdown can also be reached by adding a superexchange term to the Kondo lattice model, which mimics the intersite magnetic correlations neglected at the mean-field level.