Ab initio study of a mechanically gated molecule: From weak to strong correlation

TL;DR

This paper investigates how the electronic spectrum of a molecule in a scanning tunneling microscope junction changes with tip retraction, revealing a transition from broad quasiparticle to narrow Kondo resonance through advanced theoretical methods.

Contribution

It combines density functional, many-body perturbation, and numerical renormalization group theories to analyze electronic correlation effects in a mechanically gated molecule, capturing the transition from weak to strong correlation.

Findings

Observation of evolution from broad quasiparticle to narrow Kondo resonance

Theoretical results match experimental spectral changes

Highlights importance of non-locality and dynamics in electronic correlation

Abstract

The electronic spectrum of a chemically contacted molecule in the junction of a scanning tunneling microscope can be modified by tip retraction. We analyze this effect by a combination of density functional, many-body perturbation and numerical renormalization group theory, taking into account both the non-locality and the dynamics of electronic correlation. Our findings, in particular the evolution from a broad quasiparticle resonance below to a narrow Kondo resonance at the Fermi energy, correspond to the experimental observations.