Structural Phase Transitions by Design in Monolayer Alloys

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• 作者：Karel-Alexander N. Duerloo ; Evan J. Reed
• 刊名：ACS Nano
• 出版年：2016
• 出版时间：January 26, 2016
• 年：2016
• 卷：10
• 期：1
• 页码：289-297
• 全文大小：476K
• ISSN：1936-086X

文摘

Two-dimensional monolayer materials are a highly anomalous class of materials under vigorous exploration. Mo- and W-dichalcogenides are especially unusual two-dimensional materials because they exhibit at least three different monolayer crystal structures with strongly differing electronic properties. This intriguing yet poorly understood feature, which is not present in graphene, may support monolayer phase engineering, phase change memory and other applications. However, knowledge of the relevant phase boundaries and how to engineer them is lacking. Here we show using alloy models and state-of-the-art density functional theory calculations that alloyed MoTe₂–WTe₂ monolayers support structural phase transitions, with phase transition temperatures tunable over a large range from 0 to 933 K. We map temperature–composition phase diagrams of alloys between pure MoTe₂ and pure WTe₂, and benchmark our methods to analogous experiments on bulk materials. Our results suggest applications for two-dimensional materials as phase change materials that may provide scale, flexibility, and energy consumption advantages.