Large-Gap Quantum Spin Hall Insulator in Single Layer Bismuth Monobromide Bi4Br4
Large-Gap Quantum Spin Hall Insulator in Single Layer Bismuth Monobromide Bi4Br4
复制标题
单层一溴化铋 Bi4Br4 中的大间隙量子自旋霍尔绝缘体
DOI：
10.1021/nl501907g
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发表时间：
2014
期刊：
影响因子：
10.8
通讯作者：
Yao Yugui
中科院分区：
文献类型：
--
作者：
Zhou Jin-Jian;Feng Wanxiang;Liu Cheng-Cheng;Guan Shan;Yao Yugui
量子自旋霍尔（QSH）绝缘体在体带隙内具有无带隙拓扑边缘态，可以作为无耗散的自旋电流通道。目前的主要挑战是为这种拓扑状态找到合适的材料。在这里，我们预测了一个新的大带隙QSH绝缘体直接带隙为10.18 eV，在单层Bi4Br4，它可以剥离其三维体材料由于弱键合的层状结构。单层Bi4Br4的带隙可通过应变工程进行调节，并且QSH相对外部应变具有鲁棒性。此外，由于这种材料由特殊的一维分子链作为其基本构件，单层Bi 4Br 4可以被撕裂成具有干净和原子级尖锐边缘的条带。这些纳米带，它具有单狄拉克锥边缘状态跨越体带隙，是理想的无耗散传输线。因此，我们的工作为QSH效应的实验研究和实际应用提供了一种新的有前途的材料。
Quantum spin Hall (QSH) insulators have gapless topological edge states inside the bulk band gap, which can serve as dissipationless spin current channels. The major challenge currently is to find suitable materials for this topological state. Here, we predict a new large-gap QSH insulator with bulk direct band gap of ∼0.18 eV, in single-layer Bi4Br4, which could be exfoliated from its three-dimensional bulk material due to the weakly bonded layered structure. The band gap of single-layer Bi4Br4is tunable via strain engineering, and the QSH phase is robust against external strain. Moreover, because this material consists of special one-dimensional molecular chain as its basic building block, the single layer Bi4Br4could be torn to ribbons with clean and atomically sharp edges. These nanoribbons, which have single-Dirac-cone edge states crossing the bulk band gap, are ideal wires for dissipationless transport. Our work thus provides a new promising material for experimental studies and practical applications of the QSH effect.