Two Anderson Impurity problem: Kondo-doublets beyond the Kondo Limit

TL;DR

This paper investigates how high energy configurations influence the Kondo-doublet interaction between two Anderson impurities, revealing robustness and tunability of magnetic states near the Kondo limit.

Contribution

It provides analytic expressions for corrections beyond the Kondo limit and explores the transition between ferromagnetic and antiferromagnetic regimes.

Findings

Kondo doublet states are robust with increased coherence energy

System behavior can switch from ferromagnetic to antiferromagnetic by tuning parameters

High energy configurations significantly affect impurity interactions

Abstract

We analyze the effects of high energy configurations on the Kondo-doublet interaction between two Anderson impurities. We found that the Kondo doublet states are robust and that their coherence energy is incremented by the inclusion of high energy configurations. Analytic expressions are obtained for the corrections near the Kondo limit. Analysis of the system in the intermediate valence regime shows that the behavior of the system can be changed from ferromagnetic to sligthy antiferromagnetic by tuning the system parameters; this regime can also be used to study the interplay between hole-driven and electron-driven coherence effects.