New families of large band gap 2D topological insulators in ethynyl-derivative functionalized compounds
New families of large band gap 2D topological insulators in ethynyl-derivative functionalized compounds
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DOI：
10.1016/j.apsusc.2019.04.071
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发表时间：
2019-08
影响因子：
6.7
通讯作者：
L. Wu;Kunming Gu;Qiliang Li
中科院分区：
文献类型：
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作者：
L. Wu;Kunming Gu;Qiliang Li
寻找具有无耗散边状态的大带隙系统对于开发在宽温度范围内工作的材料是至关重要的。二维(2D)拓扑绝缘体(TIS)由于具有无耗散传输、坚固耐用和与器件集成良好的兼容性等优点，近年来引起了人们极大的关注。然而，2D TIS的一个主要障碍是其较小的体带隙，这仅允许在极低的温度下应用。本文用第一性原理计算方法研究了PbC_2X和BiC_2X(X = H，Cl，F，Br，I)化合物的几何、电子和拓扑性质。带隙非常大，从0.79 eV到0.99 eV。这些化合物的纳米带在模拟中表现出了非平凡的拓扑顺序，从而证明了乙炔基衍生物功能化的Pb膜和Bi膜是一类新的巨大带隙2D TiS。此外，这些发现表明，乙炔基衍生物的化学官能化是调节带隙和保持非平凡拓扑秩序的有效方法。这些既适用于室温又适用于高温的新型材料为新一代电子产品打开了大门。
The search for large band gap systems with dissipationless edge states is essential to developing materials that function under a wide range of temperatures. Two-dimensional (2D) topological insulators (TIs) have recently attracted significant attention due to their dissipationless transport, robust properties and excellent compatibility with device integration. However, a major barrier of 2D TIs is their small bulk band gap, which allows for applications only in extremely low temperatures. In this work, first principle calculations were used to analyze the geometric, electronic, and topological properties of PbC2X and BiC2X (X = H, Cl, F, Br, I) compounds. The band gap values are remarkably large, ranging from 0.79 eV to 0.99 eV. The nanoribbons of these compounds exhibited nontrivial topological order in the simulation, thus proving ethynyl-derivative functionalized Pb and Bi films to be new classes of giant band gap 2D TIs. In addition, these findings indicate that chemical functionalization with ethynyl-derivatives is an effective method to tune the band gap and preserve the nontrivial topological order. These novel materials that are applicable at both room temperature and high temperatures open the door to a new generation of electronics.