# Effects of finite-range interactions on the one-electron spectral properties of TTF-TCNQ

## TL;DR

This study uses advanced ARPES measurements and a refined theoretical model to analyze how finite-range electron interactions influence the high-energy spectral properties of the quasi-one-dimensional conductor TTF-TCNQ.

## Contribution

It introduces a mobile quantum impurity scheme to incorporate finite-range interactions into the 1D Hubbard model, aligning theory with experimental ARPES data at high energies.

## Key findings

- Finite-range interactions are essential to explain ARPES spectra.
- Charge fractionalized particles scatter in the unitary limit.
- Results are applicable to other 1D and quasi-1D systems.

## Abstract

The electronic dispersions of the quasi-one-dimensional organic conductor TTF-TCNQ are studied by angle-resolved photoelectron spectroscopy (ARPES) with higher angular resolution and accordingly smaller step width than in previous studies. Our experimental results suggest that a refinement of the single-band 1D Hubbard model that includes finite-range interactions is needed to explain these photoemission data. To account for the effects of these finite-range interactions we employ a mobile quantum impurity scheme that describes the scattering of fractionalized particles at energies above the standard Tomonaga-Luttinger liquid limit. Our theoretical predictions agree quantitatively with the location in the $(k,\omega)$ plane of the experimentally observed ARPES structures at these higher energies. The nonperturbative microscopic mechanisms that control the spectral properties are found to simplify in terms of the exotic scattering of the charge fractionalized particles. We find that the scattering occurs in the unitary limit of (minus) infinite scattering length, which limit occurs within neutron-neutron interactions in shells of neutron stars and in the scattering of ultracold atoms but not in perturbative electronic condensed-matter systems. Our results provide important physical information on the exotic processes involved in the finite-range electron interactions that control the high-energy spectral properties of TTF-TCNQ. Our results also apply to a wider class of 1D and quasi-1D materials and systems that are of theoretical and potential technological interest.