Temperature-dependence of the three-dimensional band structure of 1T-TaS${}_2$

The 1T polymorph of the layered transition metal dichalcogenide compound TaS${}_2$ undergoes a series of temperature-dependent phase transitions consisting of periodic structural distortions and organization of the electrons into regular patterns known as charge density waves (CDW). The different CDW phases vary remarkably in their electronic properties. The commensurate CDW phase of 1T-TaS${}_2$ has widely been studied as a quasi-two-dimensional phenomenon that coexists with a Mott insulating state. However, recent theoretical calculations predicted the coexistence of the CDW phase with a nearly one-dimensional metallic dispersion perpendicular to the crystal planes. Our recent angle-resolved photoemission spectroscopy results confirm the existence of a dispersive band which exists for all the different CDW phases at different temperatures. Here, we will give a detailed account of the three dimensional band structure of this highly correlated material.