Yang Jiali, Jin Yuanjun, Xu Wangping, Zheng Baobing, Wang Rui, Xu Hu
Institute for Structure and Function and Department of Physics , Chongqing University , Chongqing 400044 , China.
Department of Physics and Institute for Quantum Science and Engineering , Southern University of Science and Technology , Shenzhen 518055 , China.
J Phys Chem Lett. 2018 Aug 16;9(16):4783-4788. doi: 10.1021/acs.jpclett.8b01999. Epub 2018 Aug 9.
Monolayer (ML) tungsten ditelluride (WTe) is a well-known quantum spin Hall (QSH) insulator with topologically protected gapless edge states, thus promising dissipationless electronic devices. However, experimental findings exhibit the fast oxidation of ML WTe in ambient conditions. To reveal the changes of topological properties of WTe arising from oxidation, we systematically study the surface oxidation reaction of ML 1T'-WTe using first-principles calculations. The calculated results indicate that the fast oxidation of WTe originates from the existence of HO in air, which significantly promotes the oxidation of ML 1T'-WTe. More importantly, this low-coverage oxidized WTe loses its topological features and is changed into a trivial insulator. Furthermore, we propose a fully oxidized ML WTe that can still possess the QSH insulator states. The topological phase transition induced by oxidation provides exotic insight into understanding the topological features of layered transition-metal dichalcogenide materials.
单层（ML）二碲化钨（WTe）是一种著名的量子自旋霍尔（QSH）绝缘体，具有拓扑保护的无隙边缘态，因此有望用于无耗散电子器件。然而，实验结果表明ML WTe在环境条件下会快速氧化。为了揭示氧化引起的WTe拓扑性质的变化，我们使用第一性原理计算系统地研究了ML 1T'-WTe的表面氧化反应。计算结果表明，WTe的快速氧化源于空气中HO的存在，这显著促进了ML 1T'-WTe的氧化。更重要的是，这种低覆盖率的氧化WTe失去了其拓扑特征，转变为平凡绝缘体。此外，我们提出了一种完全氧化的ML WTe，它仍然可以拥有QSH绝缘体态。氧化诱导的拓扑相变为理解层状过渡金属二硫属化物材料的拓扑特征提供了奇特的见解。
