Fe-doping–induced superconductivity in the charge-density-wave system 1T-TaS 2

We report the interplay between charge-density-wave (CDW) and superconductivity of 1 T -Fe x Ta 1− x S 2 (0⩽ x ⩽0.05) single crystals. The CDW order is gradually suppressed by Fe-doping, accompanied by the disappearance of pseudogap/Mott-gap as shown by the density functional theory (DFT) calculations. The superconducting state develops at low temperatures within the CDW state for the samples with the moderate doping levels. The superconductivity strongly depends on x within a narrow range, and the maximum superconducting transition temperature is 2.8 K as x =0.02. For high doping level ( x > 0.04), the Anderson localization (AL) state appears, resulting in a large increase of resistivity. We present a complete electronic phase diagram of the 1 T -Fe x Ta 1− x S 2 system that shows a dome-like T c ( x ).