Xue Xianghong, Lin Zhihua, Gao Rui, Yang Bingzhuo, Wang Haoyu, Han Mengmeng, Han Nannan
School of Automation and Information Engineering, Xi'an University of Technology, Xi'an 710048, People's Republic of China.
Frontiers Science Center for Flexible Electronics, Institute of Flexible Electronics, Northwestern Polytechnical University, Xi'an 710072, People's Republic of China.
Nanotechnology. 2024 Oct 10;35(50). doi: 10.1088/1361-6528/ad8098.
Two-dimensional topological insulators (TIs) show great potential applications in low-power quantum computing and spintronics due to the spin-polarized gapless edge states. However, the small bandgap limits their room-temperature applications. Based on first-principles calculations, a series of CX (X = H, F, Cl, Br and I) functionalized III-V monolayers are investigated. The nontrivial bandgaps of GaBi-(CX), InBi-(CX), TlBi-(CX)and TlSb-(CX)are found to between 0.223 and 0.807 eV. For GaBi-(CX)and InBi-(CX), the topological insulating properties originate from theband inversion induced by the spin-orbital coupling (SOC) effect. While for TlBi-(CX)and TlSb-(CX), the topological insulating properties are attributed to the SOC effect-induced band splitting. The robust topological characteristics are further confirmed by topological invariantsand the test under biaxial strain. Finally, two ideal substrates are predicted to promote the applications of these TIs. These findings indicate that GaBi-(CX), InBi-(CX), TlBi-(CX)and TlSb-(CX)monolayers are good candidates for the fabrication of spintronic devices.
二维拓扑绝缘体（TIs）由于其自旋极化无隙边缘态，在低功耗量子计算和自旋电子学方面展现出巨大的潜在应用价值。然而，其小带隙限制了它们在室温下的应用。基于第一性原理计算，研究了一系列CX（X = H、F、Cl、Br和I）功能化的III-V族单层材料。发现GaBi-(CX)、InBi-(CX)、TlBi-(CX)和TlSb-(CX)的非平凡带隙在0.223至0.807电子伏特之间。对于GaBi-(CX)和InBi-(CX)，其拓扑绝缘特性源于自旋轨道耦合（SOC）效应引起的能带反转。而对于TlBi-(CX)和TlSb-(CX)，拓扑绝缘特性归因于SOC效应引起的能带分裂。通过拓扑不变量和双轴应变测试进一步证实了其稳健的拓扑特性。最后，预测了两种理想的衬底以促进这些拓扑绝缘体的应用。这些发现表明，GaBi-(CX)、InBi-(CX)、TlBi-(CX)和TlSb-(CX)单层材料是制造自旋电子器件的良好候选材料。
