Magnetic flux tuning of Fano-Kondo interplay in a parallel double quantum dot system

TL;DR

This paper explores how magnetic flux influences the Fano-Kondo effect in a double quantum dot system, revealing that magnetic fields can alter electron pathways and cause symmetry changes in Fano resonances.

Contribution

It introduces a theoretical framework combining slave-boson mean-field approximation and scattering matrix theory to analyze Fano-Kondo interplay under magnetic flux.

Findings

Magnetic field induces a gapped energy spectrum in the Kondo regime.

Magnetic flux can switch electron path preferences.

Symmetry changes in Fano resonance are linked to Kondo channels.

Abstract

We investigate the Fano-Kondo interplay in an Aharonov-Bohm ring with an embedded non-interacting quantum dot and a Coulomb interacting quantum dot. Using a slave-boson mean-field approximation we diagonalize the Hamiltonian via scattering matrix theory, and derive the conductance in the form of a Fano expression, which depends on the mean field parameters. We predict that in the Kondo regime the magnetic field leads to a gapped energy level spectrum due to hybridisation of the non-interacting QD state and the Kondo state, and can quantum-mechanically alter the electron's path preference. We demonstrate that an abrupt symmetry change in the Fano resonance, as seen experimentally, could be a consequence of an underlying Kondo channel.