Encapsulated Silicene: A Robust Large-Gap Topological Insulator.
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's 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-orbit 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.
Integrated Materials Design Centre (IMDC), School of Chemical Engineering, University of New South Wales , Sydney, NSW 2052, Australia.
Liangzhi
L
Kou
Engineering and Science, Jacobs University Bremen , Campus Ring 1, 28759 Bremen, Germany.
Yandong
Y
Ma
Max Planck Institute for Chemical Physics of Solids , Noethnitzer Str. 40, 01187 Dresden, Germany.
Binghai
B
Yan
Integrated Materials Design Centre (IMDC), School of Chemical Engineering, University of New South Wales , Sydney, NSW 2052, Australia.
Xin
X
Tan
Department of Physics and Astronomy and High Pressure Science and Engineering Center, University of Nevada , Las Vegas, Nevada 89154, United States.
Changfeng
C
Chen
Integrated Materials Design Centre (IMDC), School of Chemical Engineering, University of New South Wales , Sydney, NSW 2052, Australia.
Sean C
SC
Smith
encapsulation; first-principles calculations; large gap; proximity effect; silicene; topological insulator