论文标题
过渡金属富含半母氧化物中的非平凡拓扑阶段
Non-trivial topological phases in transition metal rich half-Heusler Oxides
论文作者
论文摘要
在发现Zincblende HGTE的二维量子旋转霍尔效应之后，已广泛探索具有无间隙表面状态和绝缘量的拓扑绝缘子。在这样的系统中，负带反演强度e $ _ {bis} $（$ = $ e $ _ {γ_6} - $ e $ _ {γ_8} <$ 0）控制着在环境条件下非主拓扑状态的鲁棒性。因此，意识到E $ _ {bis} $的大量负值一直是文献中报道的几项调查的指导动机。在这里，我们提出了一种材料设计方法，可以使用该方法来实现E $ _ {bis} $的大量负值，例如，半赫斯勒（HH）氧化物具有18个价电子构型。我们以$α$ - ，$β$ - 和$γ$ - 相（通过将过渡金属在不同的Wyckoff位置将过渡金属放置在不同的拓扑阶段）中，以$α$ - ，$β$ - 和$α$ - ，$β$ - 和$α$ - ，$β$ - 和$α$ - ，$β$ - 和$α$ - ，$β$ - 和$α$ - ，$β$ - - 和$α$ - ，$β$ - 和$α$ - ，$β$ - 和$α$ - ，ag，au）的形式探索27个HH氧化物。在这三个阶段的情况下，我们发现，$α$ - 九个HH氧化物（其中，过渡金属原子在晶体结构中占据4A Wyckoff位置）是最有前途的，非平凡的拓扑阶段，该阶段受质量 - 达尔文相对论效应增强E $ _ $ _ $ _ {BIS {BIS {BIS} $。而其他阶段被发现是微不足道的半导体或半学或金属，并且大多数是动态不稳定的。我们将重点放在$α$ - 相的rbauo上，其中$ _ {bis} $ $ -1.29 eV以及应变场对该化合物拓扑表面状态的影响。我们得出的结论是，此处介绍的HH氧化物的$α$期可以通过实验中，用于在旋转和纳米电子中的各种室温应用实验中。
Topological Insulators with gapless surface states and insulating bulk in non-centrosymmetric cubic systems have been extensively explored following the discovery of two-dimensional quantum spin hall effect in zincblende HgTe. In such systems the negative band inversion strength E$_{BIS}$ ($=$ E$_{Γ_6} -$ E$_{Γ_8} <$ 0) governs the robustness of the non-trivial topological states at ambient conditions. Hence, realizing large negative values of E$_{BIS}$ has been a guiding motivation of several investigations reported in literature. Here, we present a material design approach which can be employed to realize large negative values of E$_{BIS}$ in cubic materials such as half-Heusler (HH) oxides with 18 valence electron configurations. We explore 27 HH oxides of the form ABO (A = Li, K, Rb; B = Cu, Ag, Au) in $α$-, $β$-, and $γ$-phase (by placing transition metal atom at different Wyckoff positions) for their non-trivial topological phase. Off these three phases, we found that, the $α$-phase of nine HH oxides (wherein the transition metal atoms occupy 4a Wyckoff positions in the crystal structure) is the most promising with non-trivial topological phase which is governed by the mass-darwin relativistic effects enhancing E$_{BIS}$. Whereas the other phases were found to be either trivial semiconductors or semimetals or metals and most of them being dynamically unstable. We focus on RbAuO in $α$-phase with E$_{BIS}$ of $-$ 1.29 eV and the effect of strain fields on the topological surface states of this compound. We conclude that the $α$-phase of HH oxide presented here can be synthesized experimentally for diverse room temperature applications in spintronics and nanoelectronics.
