Connectivity dependence of Fano resonances in single molecules

TL;DR

This study investigates how molecular connectivity influences quantum interference effects, revealing that Fano resonances are connectivity-insensitive while Mach-Zehnder interference depends on connectivity, based on first principles and model analysis.

Contribution

The paper demonstrates the connectivity dependence of quantum interference features in single molecules, distinguishing Fano resonances from Mach-Zehnder interference through theoretical analysis.

Findings

Fano resonances are insensitive to molecular connectivity.

Mach-Zehnder interference features depend on connectivity.

Fano resonances coexist with multiple-path interference in anthraquinone-based molecules.

Abstract

Using a first principles approach combined with analysis of heuristic tight-binding models, we examine the connectivity dependence of two forms of quantum interference in single molecules. Based on general arguments, Fano resonances are shown to be insensitive to connectivity, while Mach-Zehnder-type interference features are shown to be connectivity dependent. This behaviour is found to occur in molecular wires containing anthraquinone units, in which the pendant carbonyl groups create Fano resonances, which coexist with multiple-path quantum interference features.