Looking for the Kondo cloud

TL;DR

This paper investigates the spatial extent of the Kondo screening cloud across different dimensions, revealing limited range in 3D and more localized behavior in lower dimensions, and proposes an experimental setup for direct measurement.

Contribution

It clarifies how the Kondo cloud's spatial distribution varies with dimensionality and links the cloud to impurity interactions, proposing a method for direct experimental detection.

Findings

In 3D, the Kondo cloud is limited to the Fermi wavelength scale.

In lower dimensions, the Kondo length governs the cloud's localization.

The Kondo cloud influences impurity-impurity interactions via the hole coherence factor.

Abstract

We study the spatial distribution of the Kondo screening cloud. We find that in 3 D the spatial range of the cloud is limited to distances of the order of the Fermi wavelength due to angular dispersion effects. In lower dimensions this effect is less important and thus the Kondo length determines the localization of the cloud around the magnetic impurity. We clarify the role of the Kondo cloud in the impurity-impurity interactions: the hole coherence factor of the Kondo-doublet interaction is proportional to the amplitude of the Kondo cloud. We single out an experimental setup in which the Kondo cloud could be directly measured.