Issue 30, 2018

Substrate-induced magnetism and topological phase transition in silicene

Abstract

Silicene has shown great potential for applications as a versatile material in nanoelectronics and is particularly promising as a building block for spintronic applications. Unfortunately, despite its intriguing properties, such as a relatively large spin–orbit interaction, one of the greatest obstacles to the use of silicene as a host material in spintronics is its lack of magnetism or a topological phase transition owing to the silicene–substrate interaction, which influences its fundamental properties and has yet to be fully investigated. Here, we show that when silicene is grown on a CeO2 substrate, an appreciable robust magnetic moment appears in silicene covalently bonded to CeO2 (111), while a topological phase transition from a topological insulator to a band insulator occurs regardless of van der Waals (vdW) interactions or covalent bonding interactions at the interface. The induced magnetism of silicene is due to the breaking of Si–Si π-bonds, which also results in a trivial topological phase. The silicene–substrate interaction, and even weak vdW forces (equivalent to an electric field), can destroy the quantum spin Hall effect (QSHE) in silicene. We propose a viable strategy—the construction of an inverse symmetrical sandwich structure (protective layer/silicene/substrate)—to preserve the quantum spin Hall (QSH) state of silicene in a system with weak vdW interactions. This work takes a critical step towards the fundamental physics and realistic applications of silicene-based spintronic devices.

Graphical abstract: Substrate-induced magnetism and topological phase transition in silicene

Supplementary files

Article information

Article type
Paper
Submitted
05 Jun 2018
Accepted
10 Jul 2018
First published
10 Jul 2018

Nanoscale, 2018,10, 14667-14677

Substrate-induced magnetism and topological phase transition in silicene

K. Yang, W. Huang, W. Hu, G. Huang and S. Wen, Nanoscale, 2018, 10, 14667 DOI: 10.1039/C8NR04570D

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