The spectral, structural and transport properties of the pseudogap system (TaSe4)2I

The room temperature “metallic” properties of the quasi-one-dimensional material (TaSe4)2I differ markedly from those expected of either a Fermi or a Luttinger Liquid, showing indications of a suppression of the density of states at the Fermi level—a pseudogap. We compute properties of the material using a simple model in which charge density wave fluctuations produce the pseudogap. The temperature dependence of the optical and DC conductivities of (TaSe4)2I from this model are in good agreement with experiment. We make predictions for core hole spectra and the NMR relaxation rate. In contrast, the predictions of a strongly correlated (Luttinger Liquid) model appear to contradict the data.