Probing the Kondo density of states in a three-terminal quantum ring

TL;DR

This paper investigates the Kondo effect in a three-terminal quantum ring, demonstrating how differential conductance measurements reveal the Kondo density of states and its splitting under bias, advancing understanding of quantum impurity systems.

Contribution

It introduces a method to directly probe the Kondo density of states in a three-terminal quantum ring, including out-of-equilibrium splitting analysis.

Findings

Differential conductance through the weakly coupled lead reflects the Kondo DOS.

Applying bias between strongly coupled leads causes splitting of the Kondo DOS.

The measurement technique distinguishes contributions of different leads to the Kondo effect.

Abstract

We have measured the Kondo effect in a quantum ring connected to three terminals. In this configuration non-linear transport measurements allow to check which lead contributes to the Kondo density of states (DOS) and which does not. When the ring is connected to two strongly and one weakly coupled leads, the measurement of the differential conductance through the weakly coupled lead allows to probe directly the Kondo DOS. In addition, by applying a bias between the two strongly coupled leads, we show the splitting of the out-of-equilibrium DOS.