Controlled Synthesis of Mo<sub><i>x</i></sub>W<sub>1-<i>x</i></sub>Te<sub>2</sub> Atomic Layers with Emergent Quantum States.

Deng, Ya; Li, Peiling; Zhu, Chao; Zhou, Jiadong; Wang, Xiaowei; Cui, Jian; Yang, Xue; Tao, Li et al. · ACS Nano · 2021

basic_science · Level V

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Abstract

Recently, new states of matter like superconducting or topological quantum states were found in transition metal dichalcogenides (TMDs) and manifested themselves in a series of exotic physical behaviors. Such phenomena have been demonstrated to exist in a series of transition metal tellurides including MoTe<sub>2</sub>, WTe<sub>2</sub>, and alloyed Mo<sub><i>x</i></sub>W<sub>1-<i>x</i></sub>Te<sub>2.</sub> However, the behaviors in the alloy system have been rarely addressed due to their difficulty in obtaining atomic layers with controlled composition, albeit the alloy offers a great platform to tune the quantum states. Here, we report a facile CVD method to synthesize the Mo<sub><i>x</i></sub>W<sub>1-<i>x</i></sub>Te<sub>2</sub> with controllable thickness and chemical composition ratios. The atomic structure of a monolayer Mo<sub><i>x</i></sub>W<sub>1-<i>x</i></sub>Te<sub>2</sub> alloy was experimentally confirmed by scanning transmission electron microscopy. Importantly, two different transport behaviors including superconducting and Weyl semimetal states were observed in Mo-rich Mo<sub>0.8</sub>W<sub>0.2</sub>Te<sub>2</sub> and W-rich Mo<sub>0.2</sub>W<sub>0.8</sub>Te<sub>2</sub> samples, respectively. Our results show that the electrical properties of Mo<sub><i>x</i></sub>W<sub>1-<i>x</i></sub>Te<sub>2</sub> can be tuned by controlling the chemical composition, demonstrating our controllable CVD growth method is an efficient strategy to manipulate the physical properties of TMDCs. Meanwhile, it provides a perspective on further comprehension and sheds light on the design of devices with topological multicomponent TMDC materials.