Mesoscopic Kondo Effect in an Aharonov-Bohm Ring

TL;DR

This paper investigates the mesoscopic Kondo effect in an Aharonov-Bohm ring with a quantum dot, revealing how electron parity influences persistent current and Kondo resonance, with implications for quantum transport.

Contribution

It introduces a variational approach to analyze the ground state of a quantum dot in a mesoscopic ring under magnetic flux, highlighting parity-dependent effects on persistent current.

Findings

Persistent current similar to a perfect ring for even electron number

Suppressed persistent current for odd electron number

Kondo resonance affects quantum transport properties

Abstract

An interacting quantum dot inserted in a mesoscopic ring is investigated. A variational ansatz is employed to describe the ground state of the system in the presence of the Aharonov-Bohm flux. It is shown that, for even number of electrons with the energy level spacing smaller than the Kondo temperature, the persistent current has a value similar to that of a perfect ring with the same radius. On the other hand, for a ring with odd number electrons, the persistent current is found to be strongly suppressed compared to that of an ideal ring, which implies the suppression of the Kondo-resonant transmission. Various aspects of the Kondo-assisted persistent current are discussed.