Aharonov-Bohm Effect for Parallel and T-shaped Double Quantum Dots

TL;DR

This paper studies how the Aharonov-Bohm effect manifests in double quantum dots within the Kondo regime, revealing a universal 2π oscillation period due to the fixed Kondo resonance, contrasting with non-interacting cases.

Contribution

It demonstrates that the AB oscillation period is 2π in the Kondo regime for double quantum dots, regardless of the interdot tunneling or geometry, highlighting the Kondo resonance's role.

Findings

AB oscillation has a period of 2π in the Kondo regime.

The Kondo resonance remains fixed at the Fermi level.

Effects are observed even in charge-fluctuation regimes.

Abstract

We investigate the Aharonov-Bohm (AB) effect for the double quantum dots in the Kondo regime using the slave-boson mean-field approximation. In contrast to the non-interacting case, where the AB oscillation generally has the period of 4$\pi$ when the two-subring structure is formed via the interdot tunneling $t_c$, we find that the AB oscillation has the period of 2$\pi$ in the Kondo regime. Such effects appear for the double quantum dots close to the T-shaped geometry even in the charge-fluctuation regime. These results follow from the fact that the Kondo resonance is always fixed to the Fermi level irrespective of the detailed structure of the bare dot-levels.