How to directly measure a Kondo cloud's length

TL;DR

This paper proposes an electrical measurement method to directly determine the length of the Kondo screening cloud by analyzing conductance changes as a function of gate voltage and impurity-wire coupling.

Contribution

It introduces a novel experimental approach to measure the Kondo cloud length directly through electrostatic gating and conductance analysis.

Findings

Kondo cloud length can be inferred from conductance variations.

Gate voltage influences the Kondo temperature and conductance.

Method enables direct experimental measurement of the Kondo cloud.

Abstract

We propose a method to directly measure, by electrical means, the Kondo screening cloud formed by an Anderson impurity coupled to semi-infinite quantum wires, on which an electrostatic gate voltage is applied at distance L from the impurity. We show that the Kondo cloud, and hence the Kondo temperature and the electron conductance through the impurity, are affected by the gate voltage, as L decreases below the Kondo cloud length. Based on this behavior, the cloud length can be experimentally identified by changing L with a keyboard type of gate voltage or tuning the coupling strength between the impurity and the wires.