The strong spin−orbit coupling (SOC) and numerous crystal phases in few−layer transition metal dichalcogenides (TMDCs) MX2 (M=W, Mo, and X=Te, Se, S) has led to a variety of novel physics, such as Ising superconductivity and quantum spin Hall effect realized in monolayer 2H− and Td−MX2, respectively. Consecutive tailoring of the MX2 structure from 2H to Td phase may realize the long−sought topological superconductivity in one material system by incorporating superconductivity and quantum spin Hall effect together. In this work, by combing Raman spectrum, X-ray photoelectron spectrum (XPS), scanning transmission electron microscopy imaging (STEM) as well as electrical transport measurements, we demonstrate that a consecutively structural phase transitions from Td to 1T′ to 2H polytype can be realized as the Se-substitution concentration increases. More importantly, the Se−substitution has been found to notably enhance the superconductivity of the MoTe2 thin film, which is interpreted as the introduction of the two−band superconductivity. The chemical constituent induced phase transition offers a new strategy to study the s+− superconductivity and the possible topological superconductivity as well as to develop phase−sensitive devices based on MX2 materials.
@article{arxiv.1907.03521,
title = {Phase evolution and superconductivity enhancement in Se-substituted MoTe$_2$ thin films},
author = {Peiling Li and Jian Cui and Jiadong Zhou and Dong Guo and Zhenzheng Zhao and Jian Yi and Jie Fan and Zhongqing Ji and Xiunian Jing and Fanming Qu and Changli Yang and Li Lu and Junhao Lin and Zheng Liu and Guangtong Liu},
journal= {arXiv preprint arXiv:1907.03521},
year = {2022}
}