Kondo screening cloud in the single-impurity Anderson model: A density matrix renormalization group study

TL;DR

This study uses the density matrix renormalization group method to analyze the spatial extent of the Kondo screening cloud in the single-impurity Anderson model, examining how it is affected by various perturbations.

Contribution

It provides a detailed analysis of the Kondo cloud's behavior and explores the relationship between the screening length and the Kondo temperature under different conditions.

Findings

Kondo screening length can be related to the inverse Kondo temperature.

Perturbations like gate potential and magnetic field affect the Kondo cloud.

The study clarifies the spatial characteristics of the Kondo effect.

Abstract

A magnetic moment in a metal or in a quantum dot is, at low temperatures, screened by the conduction electrons through the mechanism of the Kondo effect. This gives rise to spin-spin correlations between the magnetic moment and the conduction electrons, which can have a substantial spatial extension. We study this phenomenon, the so-called Kondo cloud, by means of the density matrix renormalization group method for the case of the single-impurity Anderson model. We focus on the question whether the Kondo screening length, typically assumed to be proportional to the inverse Kondo temperature, can be extracted from the spin-spin correlations. For several mechanisms -- the gate potential and a magnetic field -- which destroy the Kondo effect, we investigate the behavior of the screening cloud induced by these perturbations.