Single- and many-particle description of scanning tunneling spectroscopy

TL;DR

This paper develops theoretical methods to extend scanning tunneling spectroscopy analysis from simple single-particle models to complex many-body regimes, addressing strong electron interactions in molecules and nanostructures.

Contribution

It introduces approaches to incorporate electron-electron interactions into tunneling spectroscopy models, enhancing understanding of correlated quantum systems.

Findings

Improved interpretation of tunneling spectra in molecules with strong Coulomb interactions.

Application of models to graphene nanoribbons and phthalocyanines.

Insights into fractional quantum Hall droplets with strong correlations.

Abstract

Scanning tunneling spectroscopy measures how a single electron with definite energy propagates between a sample surface and the tip of a scanning tunneling microscope. In the simplest description, the differential conductance measured is interpreted as the local density of states of the sample at the tip position. This picture, however, is insufficient in some cases, since especially smaller molecules weakly coupled with the substrate tend to have strong Coulomb interactions when an electron is inserted or removed at the molecule. We present theoretical approaches to go from the non-interacting and single-particle picture to the correlated many-body regime. The methodology is used to understand recent experiments on finite armchair graphene nanoribbons and phthalocyanines. We also theoretically discuss the strongly-correlated model system of fractional quantum Hall droplets.