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arXiv 1806.05979cond-mat.mes-hall
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硅烯的衬底诱导磁性和拓扑相变

Substrate-induced magnetism and topological phase transition in silicene

Ke Yang, Wei-Qing Huang, Wangyu Hu, Gui-Fang Huang, Shuangchun Wen

摘要:

硅烯作为纳米电子学的多功能材料,特别是作为自旋电子学的结构单元,显示出巨大的应用潜力。不幸的是,尽管其有趣的性质,如相对较大的自旋-轨道相互作用,硅烯是有用的作为主体自旋电子材料的最大障碍之一是缺乏磁性或拓扑相变由于硅-衬底相互作用,这影响其基本性质,并尚未得到充分的探索。在这里,我们表明,当硅烯生长在CeO 2衬底上,一个可观的强大的磁矩出现在硅烯共价键合到CeO 2(111),而拓扑相变带绝缘体发生无论范德华力(vdWs)的相互作用或共价键在界面处的相互作用。硅烯的感生磁性是由于Si-Si π键的断裂,同时也导致了平凡的拓扑相。硅烯与衬底的相互作用,即使是很弱的vdWs力(相当于一个电场),也能破坏硅烯的量子自旋霍尔效应(QSHE)。我们提出了一种可行的策略-构建反对称三明治结构(保护层/硅烯/衬底)-在弱vdWs相互作用系统中保持硅烯的量子自旋霍尔(QSH)态。这项工作为硅基自旋电子器件的基础物理和实际应用迈出了关键的一步。

英文摘要:

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

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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