Ghost Fano resonance in a double quantum dot molecule attached to leads

TL;DR

This paper investigates how quantum interference affects electron transport in a double quantum dot molecule, revealing the transition from Fano resonance to localized states as the configuration symmetry increases.

Contribution

It demonstrates the evolution of Fano resonance and state localization in a double quantum dot system as the geometry transitions from series to symmetric parallel.

Findings

Fano resonance narrows and disappears with increased symmetry

Antibonding state becomes fully localized in symmetric configuration

Quantum interference suppresses tunneling through antibonding state

Abstract

We study the electronic transport through a double quantum dot molecule attached to leads, and examine the transition from a configuration in series to a symmetrical parallel geometry. We find that a progressive reduction of the tunneling through the antibonding state takes place as a result of the destructive quantum interference between the different pathways through the molecule. The Fano resonance narrows down, disappearing entirely when the configuration is totally symmetric, so that only the bonding state participates of the transmission. In this limit the antibonding state becomes completely localized.