Influence of defects on charge-density-wave and superconductivity in 1T-TaS2 and 2H-TaS2 systems

We grew pure 1T/2H-TaS2 single crystals via the chemical vapor transport (CVT) method and introduced defects into the samples by quenching. We systematically investigated the influence of defects on charge-density-wave (CDW) and superconductivity (SC) in 1T and 2H-TaS2. The defects can induce SC to 1T-TaS2 system, and inhibit the commensurate CDW (CCDW) and Mott insulator phase, the superconducting transition temperature (T-c(Onset)) is about 2.5 K and the zero resistivity temperature (T-c(zero)) is about 0.7 K. For 2H-TaS2, the defects nearly have no effect on CDW, while T-c(Onset) is increased to about 2.7 K. The magnetization hysteresis loops show typical type-II superconductor behaviors for both 1T and 2H-TaS2 systems. (C) 2013 Elsevier B. V. All rights reserved.