Encapsulated Silicene: A Robust Large-Gap Topological Insulator

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• 作者：Liangzhi Kou ; Yandong Ma ; Binghai Yan ; Xin Tan ; Changfeng Chen ; Sean C. Smith
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2015
• 出版时间：September 2, 2015
• 年：2015
• 卷：7
• 期：34
• 页码：19226-19233
• 全文大小：484K
• ISSN：1944-8252

文摘

The quantum spin Hall (QSH) effect predicted in silicene has raised exciting prospects of new device applications compatible with current microelectronic technology. Efforts to explore this novel phenomenon, however, have been impeded by fundamental challenges imposed by silicene鈥檚 small topologically nontrivial band gap and fragile electronic properties susceptible to environmental degradation effects. Here we propose a strategy to circumvent these challenges by encapsulating silicene between transition-metal dichalcogenides (TMDCs) layers. First-principles calculations show that such encapsulated silicene exhibit a two-orders-of-magnitude enhancement in its nontrivial band gap, which is driven by the strong spin鈥搊rbit coupling effect in TMDCs via the proximity effect. Moreover, the cladding TMDCs layers also shield silicene from environmental gases that are detrimental to the QSH state in free-standing silicene. The encapsulated silicene represents a novel two-dimensional topological insulator with a robust nontrivial band gap suitable for room-temperature applications, which has significant implications for innovative QSH device design and fabrication.