Many Body Effects on Electron Tunneling through Quantum Dots in an Aharonov-Bohm Circuit

TL;DR

This paper investigates how many-body interactions, specifically the Kondo effect, influence electron tunneling and Aharonov-Bohm oscillations in a quantum dot circuit across various temperatures, revealing complex harmonic behaviors.

Contribution

It provides a comprehensive numerical analysis of AB oscillations in a double quantum dot system considering many-body effects over a wide temperature range.

Findings

AB oscillations exhibit strong higher harmonics with deep dot potentials.

Temperature rise reduces AB oscillation amplitude due to decoherence.

Kondo effect induces a crossover in the spin state affecting conductance.

Abstract

Tunneling conductance of an Aharonov-Bohm circuit including two quantum dots is calculated based on the general expression of the conductance in the linear response regime of the bias voltage. The calculation is performed in a wide temperature range by using numerical renormalization group method. Various types of AB oscillations appear depending on the temperature and the potential depth of the dots. Especially, AB oscillations have strong higher harmonics components as a function of the magnetic flux when the potential of the dots is deep. This is related to the crossover of the spin state due to the Kondo effect on quantum dots. When the temperature rises up, the amplitude of the AB oscillations becomes smaller reflecting the breaking of the coherency.