A quaternary compound Bi3O2S2Cl, which consists of novel [BiS2Cl]2-layers, is reported. It adopts a layered structure of the space group I4/mmm (No. 139) with lattice parameters: a = 3.927(1) {\AA}, c = 21.720(5) {\AA}. In this compound, bismuth and chlorine atoms form an infinite planar layer, which is unique among the bismuth halides. Superconductivity is observed in both polycrystals and single crystals, and is significantly enhanced in the samples prepared with less sulfur or at higher temperatures. By tuning the content of sulfur, Bi3O2S2Cl can be converted from a semiconductor into a superconductor. The superconducting critical temperature ranges from 2.6 K to 3.5 K. Our discovery of the [BiS2Cl]2- layer opens another door in searching for the bismuth compounds with novel physical properties.
@article{arxiv.1903.02698,
title = {Superconductivity in Bi3O2S2Cl with Bi-Cl Planar Layers},
author = {Bin-Bin Ruan and Kang Zhao and Qing-Ge Mu and Bo-Jin Pan and Tong Liu and Huai-Xin Yang and Jian-Qi Li and Gen-Fu Chen and Zhi-An Ren},
journal= {arXiv preprint arXiv:1903.02698},
year = {2019}
}