Correlations between two Anderson impurities

TL;DR

This paper investigates the correlation effects between two Anderson impurities, revealing two energy scales related to spin susceptibilities and identifying a superconductivity instability near a quantum critical point.

Contribution

It introduces a detailed analysis of intersite correlations in two Anderson impurities, highlighting the presence of two distinct energy scales and a superconductivity instability.

Findings

Two characteristic energy scales linked to spin susceptibilities.

High energy scale similar to heavy fermion coherence scale.

Superconductivity instability near quantum critical point.

Abstract

We study the intersite correlation effects on the Kondo dynamics of two Anderson impurities. Two characteristic energy scales are present associated with the splitting of the uniform and staggered spin susceptibilities. The high energy scale has similar properties as the coherence scale in heavy fermion materials while the low energy scale characterizes the competing orders between Kondo singlet state and inter-impurity singlet state. A singlet superconductivity instability is found near the quantum critical point and is associated with the singular staggered spin susceptibility.