Designing 3D topological insulators by 2D-Xene (X = Ge, Sn) sheet functionalization in GaGeTe-type structures
Designing 3D topological insulators by 2D-Xene (X = Ge, Sn) sheet functionalization in GaGeTe-type structures
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DOI：
10.1039/c7tc00390k
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发表时间：
2017-04
影响因子：
6.4
通讯作者：
Florian Pielnhofer;T. Menshchikova;I. P. Rusinov;A. Zeugner;I. Sklyadneva;R. Heid;K. Bohnen;Pavlo Golu
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文献类型：
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作者：
Florian Pielnhofer;T. Menshchikova;I. P. Rusinov;A. Zeugner;I. Sklyadneva;R. Heid;K. Bohnen;Pavlo Golu
最先进的理论研究预计石墨烯的“重”类似物、独立的弯曲蜂窝状 Xene（X = Si、Ge、Sn、Pb 等）中存在二维狄拉克系统。在此，我们考虑一种 2D 片材，其结构和电子学上类似于 Xenes，具有层状 AXTe（A = Ga、In；X = Ge、Sn）块体材料的 3D 周期性菱形结构。由于 Xene 衍生物通过共价相互作用进行功能化，预计该结构族将具有 Z2 = 1;(111) 的 3D 强拓扑绝缘体。母体结构GaGeTe是一种早已为人所知的块状半导体； “重”同构类似物 InSnTe 和 GaSnTe 预计是动态稳定的。 InSnTe 中的自旋轨道相互作用打开了一个小的拓扑带隙，其带隙边缘主要由 In-5s 和 Te-5p 态组成。我们的模拟将 GaSnTe 归类为具有拓扑特性的半金属，而 GaGeTe 的结论还不是结论性的，需要进一步的实验验证。 AXTe 系列结构可被视为闪锌矿型晶格的二维分层切口的堆叠，由现代半导体器件中广泛使用的元素组成；因此，它们代表了自旋电子学应用中一种易于使用且有吸引力的替代方案。 AXTe 的层状性质应该有利于其六层的剥离和异质结构的制造。
State-of-the-art theoretical studies anticipate a 2D Dirac system in the “heavy” analogues of graphene, free-standing buckled honeycomb-like Xenes (X = Si, Ge, Sn, Pb, etc.). Herewith we regard a 2D sheet, which structurally and electronically resembles Xenes, in a 3D periodic, rhombohedral structure of layered AXTe (A = Ga, In; X = Ge, Sn) bulk materials. This structural family is predicted to host a 3D strong topological insulator with Z2 = 1;(111) as a result of functionalization of the Xene derivative by covalent interactions. The parent structure GaGeTe is a long-known bulk semiconductor; the “heavy”, isostructural analogues InSnTe and GaSnTe are predicted to be dynamically stable. Spin–orbit interaction in InSnTe opens a small topological band gap with inverted gap edges that are mainly composed of the In-5s and Te-5p states. Our simulations classify GaSnTe as a semimetal with topological properties, whereas the verdict for GaGeTe is not conclusive and urges further experimental verification. The AXTe family structures can be regarded as stacks of 2D layered cut-outs from a zincblende-type lattice and are composed of elements that are broadly used in modern semiconductor devices; hence they represent an accessible, attractive alternative for applications in spintronics. The layered nature of AXTe should facilitate the exfoliation of their hextuple layers and manufacture of heterostructures.