Proposed alteration of images of molecular orbitals obtained using a scanning tunnelling microscope as a probe of electron correlation

TL;DR

This paper demonstrates that electron correlation effects beyond mean-field significantly alter scanning tunneling spectroscopy images of molecules, especially near metal centers, and these changes are experimentally observable.

Contribution

It introduces a method to detect electron correlation effects in STS images of molecules using ab-initio many-body calculations, revealing qualitative changes beyond mean-field interpretations.

Findings

Electron correlation significantly alters STS images near metal centers.

Many-body effects change spectral weight in molecular images.

Changes are experimentally accessible and survive molecule-substrate interactions.

Abstract

Scanning tunneling spectroscopy (STS) allows to image single molecules decoupled from the supporting substrate. The obtained images are routinely interpreted as the square moduli of molecular orbitals, dressed by the mean-field electron-electron interaction. Here we demonstrate that the effect of electron correlation beyond mean field qualitatively alters the uncorrelated STS images. Our evidence is based on the ab-initio many-body calculation of STS images of planar molecules with metal centers. We find that many-body correlations alter significantly the image spectral weight close to the metal center of the molecules. This change is large enough to be accessed experimentally, surviving to molecule-substrate interactions.