Kondo resonance effect on persistent currents through a quantum dot in a mesoscopic ring

TL;DR

This paper investigates how the Kondo resonance influences persistent currents in a mesoscopic ring with a quantum dot, revealing enhanced current scaling behavior in the Kondo regime and proposing experimental detection methods.

Contribution

It introduces an exact diagonalization approach to study the Kondo effect on persistent currents and uncovers a distinct $L^{-1/2}$ scaling in the Kondo regime.

Findings

Kondo resonance enhances persistent current compared to resonance or perfect ring cases.

Persistent current scales as $L^{-1/2}$ in the Kondo regime, differing from the $L^{-1}$ scaling of a perfect ring.

Detection of the Kondo effect via persistent current measurements is feasible.

Abstract

The persistent current through a quantum dot inserted in a mesoscopic ring of length L is studied. A cluster representing the dot and its vicinity is exactly diagonalized and embedded into the rest of the ring. The Kondo resonance provides a new channel for the current to flow. It is shown that due to scaling properties, the persistent current at the Kondo regime is enhanced relative to the current flowing either when the dot is at resonance or along a perfect ring of same length. In the Kondo regime the current scales as $L^{-1/2}$, unlike the $L^{-1}$ scaling of a perfect ring. We discuss the possibility of detection of the Kondo effect by means of a persistent current measurement.