Charge transport through extended molecular wires with strongly correlated electrons.

James O Thomas,G Andrew D Briggs,Jan A Mol,George C Schatz,Jakub K Sowa,Sumit Tewari,Harry L Anderson,Jonathan Baugh,Charalambos Evangeli,Jacob L Swett,Bart Limburg,Xinya Bian

doi:10.1039/d1sc03050g

Abstract

Electron–electron interactions are at the heart of chemistry and understanding how to control them is crucial for the development of molecular-scale electronic devices. Here, we investigate single-electron tunneling through a redox-active edge-fused porphyrin trimer and demonstrate that its transport behavior is well described by the Hubbard dimer model, providing insights into the role of electron–electron interactions in charge transport. In particular, we empirically determine the molecule's on-site and inter-site electron–electron repulsion energies, which are in good agreement with density functional calculations, and establish the molecular electronic structure within various oxidation states. The gate-dependent rectification behavior confirms the selection rules and state degeneracies deduced from the Hubbard model. We demonstrate that current flow through the molecule is governed by a non-trivial set of vibrationally coupled electronic transitions between various many-body ground and excited states, and experimentally confirm the importance of electron–electron interactions in single-molecule devices.

Highlights

Charge transport is one of the key observables in quantum systems, yet its interpretation is o en complicated by strong many-body correlations
We investigate single-electron tunneling through a redox-active edge-fused porphyrin trimer and demonstrate that its transport behavior is well described by the Hubbard dimer model, providing insights into the role of electron– electron interactions in charge transport
The longest wavelength absorbance maximum in the optical absorbance spectrum of FP3 is at 1500 nm (0.83 eV), We have previously shown that the porphyrin monomer with the same electron-rich TDP anchor groups is commonly found in the oxidized N À 1 state upon adsorption onto pdoped graphene electrodes at zero gate voltage, Vg 1⁄4 0.29 FP3 is more readily oxidized when compared to the monomer

Summary

Introduction

Charge transport is one of the key observables in quantum systems, yet its interpretation is o en complicated by strong many-body correlations. By considering the experimental addition energies of device A in the extended Hubbard framework, we are able to determine the electron– electron repulsion terms U z 0.5 eV and V z 0.14 eV; from the recti cation behavior and DFT calculations (discussed below), we infer below that U, V [ t.

Results

Conclusion