Intersite coupling effects in a Kondo lattice

TL;DR

This study investigates how intersite interactions influence the electronic and magnetic properties of a Kondo lattice, revealing two distinct energy scales and different ground states in dilute versus dense regimes.

Contribution

It identifies and characterizes two separate energy scales in a Kondo lattice, highlighting the role of intersite correlations in non-Fermi-liquid behavior.

Findings

Two energy scales: T_K and T^*.

Fermi liquid ground state in dilute alloy.

Non-Fermi-liquid behavior in dense regime.

Abstract

The La dilution of the Kondo lattice CeCoIn_5 is studied. The scaling laws found for the magnetic susceptibility and the specific heat reveal two well-separated energy scales, corresponding to the single impurity Kondo temperature T_K and an intersite spin-liquid temperature T^*. The Ce-dilute alloy has the expected Fermi liquid ground state, while the specific heat and resistivity in the dense Kondo regime exhibit non-Fermi-liquid behavior, which scales with T^*. These observations indicate that the screening of the magnetic moments in the lattice involves antiferromagnetic intersite correlations with a larger energy scale in comparison with the Kondo impurity case.