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

The angle-resolved photoemission spectrum of the quasi-one-dimensional organic-conductor TTF-TCNQ exhibits an unusual temperature dependence in the sense that a transfer of spectral weight over an energy range of $\approx 1$\textit{eV} takes place as the temperature decreases below 260$K$. In order to investigate the origin of this behavior, we have performed Dynamical Density-Matrix-Renomalization-Group (DDMRG) calculations at zero temperature and Quantum Monte Carlo (QMC) calculations at finite temperatures for the single-particle spectral weight of the doped one-dimensional (1D) Hubbard model. We present DDMRG and QMC results for a range of the model parameters of the 1D Hubbard model and make comparisons with the photoemission data. In addition, we present zero-temperature DDMRG results on the doped 1D Hubbard-Holstein model in order to explore how the electron-phonon coupling influences the single-particle spectrum in 1D correlated conductors.