Two Anderson Impurities in the Kondo Limit, Doublet States

TL;DR

This paper investigates the energy states of two Anderson impurities, revealing that doublet states can be energetically favorable over traditional singlet and triplet states depending on impurity distance, due to a coherence-enhanced Kondo interaction.

Contribution

It introduces a detailed analysis of doublet states in the two Anderson impurity problem, highlighting their energetic stability across various impurity distances.

Findings

Doublet states are lower in energy than triplet and singlet states at short distances.

Doublet states remain energetically favorable at medium to long distances for most cases.

The energy gain is attributed to a coherence-enhanced Kondo-like interaction.

Abstract

We analyze two pairs of doublet states for the two Anderson impurity problem. We found that for short interimpurity distances they have a lower energy than the ferro triplet and the antiferro singlet. For medium to long distances between the impurities, the doublets also have a lower energy than the two decoupled Kondo-singlet state for most of the range of interest. The mechanism behind their energy gain is an coherence enhanced Kondo-like interaction.