Deng Ya, Li Peiling, Zhu Chao, Zhou Jiadong, Wang Xiaowei, Cui Jian, Yang Xue, Tao Li, Zeng Qingsheng, Duan Ruihuan, Fu Qundong, Zhu Chao, Xu Jianbin, Qu Fanming, Yang Changli, Jing Xiunian, Lu Li, Liu Guangtong, Liu Zheng
School of Materials Science & Engineering, Nanyang Technological University, Singapore 639798, Singapore.
Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
ACS Nano. 2021 Jul 27;15(7):11526-11534. doi: 10.1021/acsnano.1c01441. Epub 2021 Jun 23.
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, WTe, and alloyed MoWTe 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 MoWTe with controllable thickness and chemical composition ratios. The atomic structure of a monolayer MoWTe 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 MoWTe and W-rich MoWTe samples, respectively. Our results show that the electrical properties of MoWTe 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.
最近，在过渡金属二硫属化物（TMDs）中发现了诸如超导或拓扑量子态等新的物质状态，并在一系列奇异的物理行为中表现出来。已证明此类现象存在于包括MoTe、WTe和合金化MoWTe在内的一系列过渡金属碲化物中。然而，尽管合金为调节量子态提供了一个很好的平台，但由于难以获得具有可控成分的原子层，合金体系中的行为很少得到研究。在此，我们报道了一种简便的化学气相沉积（CVD）方法来合成具有可控厚度和化学成分比的MoWTe。通过扫描透射电子显微镜从实验上证实了单层MoWTe合金的原子结构。重要的是，在富Mo的MoWTe和富W的MoWTe样品中分别观察到了两种不同的输运行为，包括超导态和外尔半金属态。我们的结果表明，通过控制化学成分可以调节MoWTe的电学性质，这表明我们的可控CVD生长方法是操纵TMDCs物理性质的有效策略。同时，它为进一步理解提供了一个视角，并为拓扑多组分TMDC材料的器件设计提供了思路。
