After our first discovery of superconductivity (SC) with TC=3.7 K in TlNi2Se2, we grew successfully a series of TlNi2Se2−xSx (0.0 ≤ x ≤2.0) single crystals. The measurements of resistivity, susceptibility and specific heat were carried out. We found that SC with TC=2.3 K also emerges in TlNi2S2 crystal, which appears to involve heavy electrons with an effective mass m∗=13∼25 mb, as inferred from the normal state electronic specific heat and the upper critical field, HC2(T). It was found that the TC and superconducting volume fraction in TlNi2Se2−xSx crystals changes with the disorder degree induced by the partial substitution of S for Se, which is characterized by the residual resistivity ratio (\textit{RRR}). The effect of the disorder on SC may provide some information for understanding the mechanism of SC in this new Ni-chalcogenide system.
@article{arxiv.1305.1033,
title = {Superconductivity and Disorder Effect in TlNi$_2$Se$_{2-x}$S$_x$ crystals},
author = {Hangdong Wang and Chiheng Dong and Qianhui Mao and Rajwali Khan and Xi Zhou and Chenxia Li and Bin Chen and Jinhu Yang and Minghu Fang},
journal= {arXiv preprint arXiv:1305.1033},
year = {2015}
}