Topological phase transition in the ternary half-Heusler alloy ZrIrBi
Topological phase transition in the ternary half-Heusler alloy ZrIrBi
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DOI：
10.1103/physrevb.97.075302
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发表时间：
2018-02-06
影响因子：
3.7
通讯作者：
Alam, Aftab
中科院分区：
文献类型：
--
作者：
Barman, C. K.;Alam, Aftab
半Heusler合金提供了一个新的平台，通过调整其杂化强度（通过晶格参数），自旋轨道强度，取代/掺杂等固有的灵活性，衍生出一系列拓扑奇异的化合物。使用密度泛函理论的第一性原理计算，我们探索在一个新的半Heusler材料ZrIrBi中实现拓扑绝缘相的可能性。我们发现了三条路线，通过它ZrIrBi可以转化为表现出拓扑非平凡相。它们是（i）1%的流体静力膨胀导致带隙反转为零，（ii）沿沿着（001）方向的单轴应变打开带隙，同时保持反转的带阶，以及（iii）用As取代50%的Bi和用Hf取代50%的Zr形成化合物ZrIr（As0.5Bi0.5）和（Zr0.5Hf0.5）IrBi，再次显示拓扑非平凡的带反转。在所有三种情况下的表面导电的一个明确的证明是通过模拟表面能带结构。我们报告的形成能和声子色散的三种情况下，以确认化合物的化学和机械稳定性。
Half-Heusler alloys provide a new platform for deriving a host of topologically exotic compounds through the inherent flexibility of tuning their hybridization strength (via lattice parameters), spin-orbit strength, substitution/doping, etc. Using the first-principles calculation within the density functional theory, we explore the possibility of realizing a topological insulating phase in a new half-Heusler material ZrIrBi. We discovered three routes through which ZrIrBi can be transformed to exhibit a topological nontrivial phase. They are (i) a hydrostatic expansion by 1% causing a band inversion with zero gap, (ii) a uniaxial strain along (001) direction which opens a band gap while preserving the inverted band order, and (iii) substitution of 50% Bi by As and 50% Zr by Hf forming the compounds ZrIr(As0.5Bi0.5) and (Zr0.5Hf0.5) IrBi again showing a topologically nontrivial band inversion. A definitive proof of the surface conduction in all three cases are done by simulating surface band structures. We report the formation energies and the phonon dispersion for the three cases to confirm the chemical and mechanical stability of the compounds.