A new kind of 2D topological insulators BiCN with a giant gap and its substrate effects.
A new kind of 2D topological insulators BiCN with a giant gap and its substrate effects.
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一种新型大间隙二维拓扑绝缘体BiCN及其衬底效应
DOI：
10.1038/srep30003
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发表时间：
2016-07-21
影响因子：
4.6
通讯作者：
Liu CC
中科院分区：
文献类型：
--
作者：
Fu B;Ge Y;Su W;Guo W;Liu CC
基于DFT计算，我们预测BiCN，即，双分子层Bi薄膜是一种新型的二维Bi基材料，具有很高的热力学稳定性，通过对拓扑不变量Z2的直接计算和螺旋边态的明显显示，证明了它也是一种具有巨大SOC带隙（~1 eV）的新型二维TI。单层h-BN和MoS 2被认为是支持二维TI薄膜的非平凡拓扑绝缘相的良好候选衬底，因为这两种衬底可以通过货车德瓦尔斯相互作用稳定并与BiCN弱相互作用，因此几乎不影响电子性质，特别是能带拓扑。拓扑性质对应变和电场是鲁棒的。这可能为实现新的拓扑相提供一个有前途的平台。
Based on DFT calculation, we predict that BiCN, i.e., bilayer Bi films passivated with -CN group, is a novel 2D Bi-based material with highly thermodynamic stability and demonstrate that it is also a new kind of 2D TI with a giant SOC gap (~1 eV) by direct calculation of the topological invariantZ2and obvious exhibition of the helical edge states. Monolayer h-BN and MoS2are identified as good candidate substrates for supporting the nontrivial topological insulating phase of the 2D TI films, since the two substrates can stabilize and weakly interact with BiCN via van der Waals interaction and thus hardly affect the electronic properties, especially the band topology. The topological properties are robust against the strain and electric field. This may provide a promising platform for realization of novel topological phases.