凝聚态物理
硫系化合物
电场
物理
拓扑绝缘体
带隙
电介质
材料科学
过渡金属
硅烯
石墨烯
化学
光电子学
纳米技术
量子力学
催化作用
生物化学
作者
Xiaofeng Qian,Junwei Liu,Liang Fu,Ju Li
出处
期刊:Science
[American Association for the Advancement of Science (AAAS)]
日期:2014-12-12
卷期号:346 (6215): 1344-1347
被引量:1524
标识
DOI:10.1126/science.1256815
摘要
Quantum spin Hall (QSH) effect materials feature edge states that are topologically protected from backscattering. However, the small band gap in materials that have been identified as QSH insulators limits applications. We use first-principles calculations to predict a class of large-gap QSH insulators in two-dimensional transition metal dichalcogenides with 1T′ structure, namely, 1T′-MX 2 with M = (tungsten or molybdenum) and X = (tellurium, selenium, or sulfur). A structural distortion causes an intrinsic band inversion between chalcogenide- p and metal- d bands. Additionally, spin-orbit coupling opens a gap that is tunable by vertical electric field and strain. We propose a topological field effect transistor made of van der Waals heterostructures of 1T′-MX 2 and two-dimensional dielectric layers that can be rapidly switched off by electric field through a topological phase transition instead of carrier depletion.
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