(TaSe4)3I: Reconciling transport, optics and ARPES

Recently, the quasi one-dimensional transition metal tetrachalcogenide (TaSe4)3 I has been found to display the coexistence between superconductivity and ferromagnetism. This result is conflicted with the previous works on this material, which overall predict it to be insulating. Furthermore, no consensus exist on the electronic properties of (TaSe4)3I in the literature, since ARPES and transport measurements disagree by an order of magnitude on its electronic bandgap. In this work, we rationalize the observed transport gaps and reconcile them with ARPES and optical experiments by relating the dissimilarities with band-folding due to an approximated translational symmetry due to distortion caused by Se cages. Finally, we relate the observed superconducting behavior to a possible extrinsic hole doping which can tune the Fermi level through a Van Hove singularity.