Tunable Kondo screening in a quantum dot device

TL;DR

This paper explores how a two-quantum-dot device influences electron transport and Kondo screening, revealing a tunable crossover between fully screened and under-screened Kondo effects through conductance measurements.

Contribution

It introduces a novel two-dot device setup that enables the study of the crossover between different Kondo screening regimes in a controllable manner.

Findings

Observation of temperature-dependent conductance due to Kondo effect.

Identification of the crossover between fully screened and under-screened Kondo regimes.

Demonstration of tunable Kondo screening via device geometry.

Abstract

We consider electron transport along a single-mode channel which is in contact, via tunnel junctions in its walls, with two quantum dots. Electron tunneling to and from the dots contributes to the electron backscattering, and thus modifies the channel conductance. If the dots carry spin, the channel conductance becomes temperature dependent due to the Kondo effect. The two-dot device geometry allows for a formation of S=1 localized spin due to the indirect exchange interaction, called Ruderman-Kittel-Kasuya-Yosida interaction. This device offers a possibility to study the crossover between fully screened and under-screened Kondo impurity. We investigate the manifestation of such crossover in the channel conductance.