Experimental observation of metallic states with different dimensionality in a quasi-one-dimensional charge density wave compound

TaTe4 is a quasi-one-dimensional tetrachalcogenide that exhibits a charge density wave (CDW) instability caused by a periodic lattice distortion. Recently, pressure-induced superconductivity has been achieved in this compound, revealing a competition between these different ground states and making TaTe4 very interesting for fundamental studies. Although TaTe4 exhibits CDW ordering below 475 K, transport experiments have reported metallic behavior with a resistivity plateau at temperatures lower than 10 K. In this paper, we study the electronic structure of TaTe4 using a combination of high-resolution angle-resolved photoemission spectroscopy and density functional calculations. Our results reveal the existence of the long-sought metallic states. These states exhibit mixed dimensionality, while some of them might have potential topological properties.