Superconductivity Induced by the Suppression of a Charge-Density-Wave Type Structural Transition in Distorted 1T-TaTe ₂ Single Crystals

We report the structural, transport, and thermoelectric properties of Ta(Te1−xSex)2 (0 ≤ x ≤ 0.5) single crystals, which show a charge-density-wave (CDW)-like structural transition at TCDW = 180 K for x = 0, that is gradually suppressed for 0 ≤ x ≤ 0.05, as a result of the local Ta–Ta/Ta–Te(Se) bonding instability. Superconductivity (SC) emerges around the critical doping level x = 0.05, indicating that there is competition between SC and CDW. The onset of TC is enhanced for x = 0.1, however, the ratio of its TC to the Fermi temperature TF is small, corresponding to weak electronic correlations. With increasing x, the monoclinic structural distortion disappears for x ≥ 0.25. These results not only demonstrate the interplay between competing electronic orders but also provide fundamental insights into the complex electron-lattice-bond coupled phenomena in TaTe2.