Published on Nature Materials (15 April 2021)

Author(s): Zhuangchai Lai, Qiyuan He, Thu Ha Tran, D. V. Maheswar Repaka, Dong-Dong Zhou, Ying Sun, Shibo Xi, Yongxin Li, Apoorva Chaturvedi, Chaoliang Tan, Bo Chen, Gwang-Hyeon Nam, Bing Li, Chongyi Ling, Wei Zhai, Zhenyu Shi, Dianyi Hu, Vinay Sharma, Zhaoning Hu, Ye Chen, Zhicheng Zhang, Yifu Yu, Xiao Renshaw Wang, Raju V. Ramanujan, Yanming Ma, Kedar Hippalgaonkar* & Hua Zhang*

Abstract

Metastable 1T′-phase transition metal dichalcogenides (1T′-TMDs) with semi-metallic natures have attracted increasing interest owing to their uniquely distorted structures and fascinating phase-dependent physicochemical properties. However, the synthesis of high-quality metastable 1T′-TMD crystals, especially for the group VIB TMDs, remains a challenge. Here, we report a general synthetic method for the large-scale preparation of metastable 1T′-phase group VIB TMDs, including WS₂, WSe₂, MoS₂, MoSe₂, WS_2xSe_2(1−x) and MoS_2xSe_2(1−x). We solve the crystal structures of 1T′-WS₂, -WSe₂, -MoS₂ and -MoSe₂ with single-crystal X-ray diffraction. The as-prepared 1T′-WS₂ exhibits thickness-dependent intrinsic superconductivity, showing critical transition temperatures of 8.6 K for the thickness of 90.1 nm and 5.7 K for the single layer, which we attribute to the high intrinsic carrier concentration and the semi-metallic nature of 1T′-WS₂. This synthesis method will allow a more systematic investigation of the intrinsic properties of metastable TMDs.

Read more: https://doi.org/10.1038/s41563-021-00971-y