Anomalous temperature dependence of the single-particle spectrum in the organic conductor TTF-TCNQ

TL;DR

This study investigates the temperature-dependent spectral weight transfer in TTF-TCNQ using numerical models, revealing that long-range Coulomb interactions are essential to explain the observed phenomena.

Contribution

The paper demonstrates that including long-range Coulomb interactions in models is necessary to accurately reproduce the temperature dependence of spectral weight in TTF-TCNQ.

Findings

Spectral weight transfer occurs over a wide energy range between 60K and 260K.

The 1D Hubbard model alone cannot explain the temperature dependence.

Long-range Coulomb interactions are crucial for matching experimental data.

Abstract

The angle-resolved photoemission spectrum of the organic conductor TTF-TCNQ exhibits an unusual transfer of spectral weight over a wide energy range for temperatures 60K<T<260K. In order to investigate the origin of this finding, here we report numerical results on the single-particle spectral weight A(k,omega) for the one-dimensional (1D) Hubbard model and, in addition, for the 1D extended Hubbard and the 1D Hubbard-Holstein models. Comparisons with the photoemission data suggest that the 1D Hubbard model is not sufficient for explaining the unusual T dependence, and the long-range part of the Coulomb repulsion also needs to be included.