Effect of band filling in the Kondo lattice: A mean-field approach

TL;DR

This paper uses a mean-field approach to study how band filling affects the competition between Kondo screening and magnetic correlations in the Kondo lattice, revealing phase coexistence and suppression of the Kondo effect away from half filling.

Contribution

It introduces a mean-field scheme with two parameters to analyze the interplay of Kondo effect and magnetic correlations as a function of band filling.

Findings

Kondo effect is suppressed away from half filling.

Magnetic correlations can persist with strong Heisenberg coupling.

Enhanced specific heat coefficient observed at low temperatures.

Abstract

The usual Kondo-lattice, including an antiferromagnetic exchange interaction between nearest-neighboring localized spins, is treated here in a mean-field scheme that introduces two mean-field parameters: one associated with the local Kondo effect, and the other related to the magnetic correlations between localized spins. Phases with short-range magnetic correlations or coexistence between those and the Kondo effect are obtained. By varying the number of electrons in the conduction band, we notice that the Kondo effect tends to be suppressed away from half filling, while magnetic correlations can survive if the Heisenberg coupling is strong enough. An enhanced linear coefficient of the specific heat is obtained at low temperatures in the metallic state.