Kondo effect in a few-electron quantum ring

TL;DR

This study investigates the Kondo effect in a small, few-electron quantum ring through transport spectroscopy, revealing insights into spin structure, Coulomb interactions, and magnetic field influences on quantum interference phenomena.

Contribution

It demonstrates the observation of the Kondo effect in a quantum ring with less than 10 electrons and explores its impact on Aharonov-Bohm oscillations under various conditions.

Findings

Kondo effect observed in a small quantum ring with <10 electrons

Aharonov-Bohm oscillations influenced by Coulomb interaction and phase jumps

Linear shifts of oscillation maxima with magnetic field and gate voltage

Abstract

A small quantum ring with less than 10 electrons was studied by transport spectroscopy. For strong coupling to the leads a Kondo effect is observed and used to characterize the spin structure of the system in a wide range of magnetic fields. At small magnetic fields Aharonov-Bohm oscillations influenced by Coulomb interaction appear. They exhibit phase jumps by $\pi$ at the Coulomb-blockade resonances. Inside Coulomb-blockade valleys the Aharonov-Bohm oscillations can also be studied due to the finite conductance caused by the Kondo effect. Astonishingly, the maxima of the oscillations show linear shifts with magnetic field and gate voltage.