Extended Hubbard Model realized in 2D clusters of molecular anions

Fuente: arXiv
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Main Authors: Tong, Oliver, Cochrane, Katherine A., Yuan, Bingkai, Roussy, Tanya, Berciu, Mona, Burke, Sarah A.
Format: Preprint
Published: 2025
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author Tong, Oliver
Cochrane, Katherine A.
Yuan, Bingkai
Roussy, Tanya
Berciu, Mona
Burke, Sarah A.
author_facet Tong, Oliver
Cochrane, Katherine A.
Yuan, Bingkai
Roussy, Tanya
Berciu, Mona
Burke, Sarah A.
contents The Hubbard model, despite its simplicity, is remarkably successful at describing numerous many-body phenomena. However, due to the small class of problems which can be solved exactly, there has been substantial interest in quantum simulations of extended Hubbard models to in turn, simulate materials and the interaction-driven phases they host. Here, we study small clusters of molecular anions of 3,4,9,10-perylene tetracarboxylic dianhydride on NaCl bilayers on Ag(111) using non-contact Atomic Force Microscopy, Electrostatic Force Spectroscopy, and Scanning Tunnelling Microscopy and Spectroscopy, and show that the occupation and transition energies are well described by an extended Hubbard model. In particular, asymmetric clusters of four molecules require the addition of differing inter-site electrostatic interaction terms and on-site potentials, as well as asymmetric hoping terms. With $t<<U$, occupation asymmetry is driven by these terms, independent of U. The good agreement between the model and the data indicate such molecular anion clusters could be used to probe larger systems and a more varied phase space of realistic fermionic Hubbard models.
format Preprint
id arxiv_https___arxiv_org_abs_2509_05868
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Extended Hubbard Model realized in 2D clusters of molecular anions
Tong, Oliver
Cochrane, Katherine A.
Yuan, Bingkai
Roussy, Tanya
Berciu, Mona
Burke, Sarah A.
Mesoscale and Nanoscale Physics
Strongly Correlated Electrons
The Hubbard model, despite its simplicity, is remarkably successful at describing numerous many-body phenomena. However, due to the small class of problems which can be solved exactly, there has been substantial interest in quantum simulations of extended Hubbard models to in turn, simulate materials and the interaction-driven phases they host. Here, we study small clusters of molecular anions of 3,4,9,10-perylene tetracarboxylic dianhydride on NaCl bilayers on Ag(111) using non-contact Atomic Force Microscopy, Electrostatic Force Spectroscopy, and Scanning Tunnelling Microscopy and Spectroscopy, and show that the occupation and transition energies are well described by an extended Hubbard model. In particular, asymmetric clusters of four molecules require the addition of differing inter-site electrostatic interaction terms and on-site potentials, as well as asymmetric hoping terms. With $t<<U$, occupation asymmetry is driven by these terms, independent of U. The good agreement between the model and the data indicate such molecular anion clusters could be used to probe larger systems and a more varied phase space of realistic fermionic Hubbard models.
title Extended Hubbard Model realized in 2D clusters of molecular anions
topic Mesoscale and Nanoscale Physics
Strongly Correlated Electrons
url https://arxiv.org/abs/2509.05868