Kondo screening cloud in a double-quantum dot system

TL;DR

This paper studies how two quantum impurities interact via RKKY coupling in a finite wire, showing that the interaction can be controlled by gating and that finite size effects influence the Kondo screening cloud.

Contribution

It demonstrates control of RKKY interaction sign through gating and explores finite size effects on Kondo screening in a double-quantum dot system.

Findings

RKKY interaction sign can be tuned by gating the wire

Impurities interact when Kondo cloud exceeds wire length

Finite size effects influence Kondo screening cloud length

Abstract

We analyze the transport properties of two artificial magnetic impurities coupled togethervia a tunable RKKY interaction mediated by conduction electrons of a finite size one dimensional wire. We show that the sign of the RKKY interaction can be controlled by gating the wire. We investigate the interplay between finite size effects and RKKY interaction and found that the two artificial impurities start to interact each-other as soon as the Kondo screening cloud length becomes larger that the length of the wire. This should allow to give a lower experimental estimate of the Kondo screening cloud length.