Charge Mediated Reversible Metal–Insulator Transition in Monolayer MoTe2 and WxMo1–xTe2 Alloy

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• 作者：Chenxi Zhang ; Santosh KC ; Yifan Nie ; Chaoping Liang ; William G. Vandenberghe ; Roberto C. Longo ; Yongping Zheng ; Fantai Kong ; Suklyun Hong ; Robert M. Wallace ; Kyeongjae Cho
• 刊名：ACS Nano
• 出版年：2016
• 出版时间：August 23, 2016
• 年：2016
• 卷：10
• 期：8
• 页码：7370-7375
• 全文大小：373K
• 年卷期：0
• ISSN：1936-086X

文摘

Metal–insulator transitions in low-dimensional materials under ambient conditions are rare and worth pursuing due to their intriguing physics and rich device applications. Monolayer MoTe₂ and WTe₂ are distinguished from other TMDs by the existence of an exceptional semimetallic distorted octahedral structure (T′) with a quite small energy difference from the semiconducting H phase. In the process of transition metal alloying, an equal stability point of the H and the T′ phase is observed in the formation energy diagram of monolayer W_xMo_1–xTe₂. This thermodynamically driven phase transition enables a controlled synthesis of the desired phase (H or T′) of monolayer W_xMo_1–xTe₂ using a growth method such as chemical vapor deposition (CVD) and molecular beam epitaxy (MBE). Furthermore, charge mediation, as a more feasible method, is found to make the T′ phase more stable than the H phase and induce a phase transition from the H phase (semiconducting) to the T′ phase (semimetallic) in monolayer W_xMo_1–xTe₂ alloy. This suggests that a dynamic metal–insulator phase transition can be induced, which can be exploited for rich phase transition applications in two-dimensional nanoelectronics.