Competition between Kondo screening and indirect magnetic exchange in a quantum box

TL;DR

This paper investigates the complex interplay between Kondo screening and indirect magnetic exchange in nanoscale metal-atom systems, revealing unconventional behaviors influenced by impurity positions and observable through magnetic field responses.

Contribution

It uncovers a re-entrant competition between Kondo and magnetic exchange interactions, showing deviations from standard theory based on impurity positioning effects.

Findings

Ground-state spin deviations from standard predictions

Energy scale larger than environmental level width

Magnetic field dependence as an experimental signature

Abstract

Nanoscale systems of metal atoms antiferromagnetically exchange coupled to several magnetic impurities are shown to exhibit an unconventional re-entrant competition between Kondo screening and indirect magnetic exchange interaction. Depending on the atomic positions of the magnetic moments, the total ground-state spin deviates from predictions of standard Ruderman-Kittel-Kasuya-Yosida perturbation theory. The effect shows up on an energy scale larger than the level width induced by the coupling to the environment and is experimentally verifiable by studying magnetic field dependencies.