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

¹ Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences Hefei 230031, PRC
² High Magnetic Field Laboratory, Chinese Academy of Sciences - Hefei 230031, PRC

^a wjlu@issp.ac.cn
^b ypsun@issp.ac.cn

Received: 9 December 2011
Accepted: 17 February 2012

Abstract

We report the interplay between charge-density-wave (CDW) and superconductivity of 1T-Fe_xTa_{1− x}S₂ (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 1T-Fe_xTa_{1− x}S₂ system that shows a dome-like T_c(x).