Fe-doping induced superconductivity in charge-density-wave system 1T-TaS2

TL;DR

This study demonstrates that Fe-doping in 1T-TaS2 suppresses charge-density-wave order and induces superconductivity with a maximum T_c of 2.8 K at x=0.02, revealing a dome-shaped phase diagram and phase separation.

Contribution

It provides the first detailed phase diagram of Fe-doped 1T-TaS2, showing the emergence of superconductivity and its relation to CDW suppression and Anderson localization.

Findings

Superconductivity appears at low temperatures for moderate Fe doping.

Maximum T_c of 2.8 K occurs at x=0.02.

High doping leads to Anderson localization and increased resistivity.

Abstract

We report the interplay between charge-density-wave (CDW) and superconductivity of 1$T$-Fe$_{x}$Ta$_{1-x}$S$_{2}$ ($0\leq x \leq 0.05$) 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 $x=0.02$. We propose that the induced superconductivity and CDW phases are separated in real space. 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 1$T$-Fe$_{x}$Ta$_{1-x}$S$_{2}$ system that shows a dome-like $T_{c}(x)$.