Structurally unstable A III BiO 3 perovskites are predicted to be topological insulators but their stable structural forms are trivial band insulators
Structurally unstable A III BiO 3 perovskites are predicted to be topological insulators but their stable structural forms are trivial band insulators
复制标题
结构不稳定的 A III BiO 3 钙钛矿被预测为拓扑绝缘体，但其稳定的结构形式是平凡带绝缘体
DOI：
10.1103/physrevb.90.161111
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发表时间：
2014
影响因子：
3.7
通讯作者：
A. Zunger
中科院分区：
文献类型：
--
作者：
G. Trimarchi;Xiuwen Zhang;A. Freeman;A. Zunger
最近，对扩大拓扑绝缘体(TIS)材料基础的探索导致了从假定晶体结构中的各种候选化合物的能带结构中探索性地计算拓扑Z2度量。然而，结构变换，如体积压缩、晶格应变或原子交换，用来在平凡的绝缘体中引发基于TI的能带反转，也可能使系统不稳定，以至于它要么扭曲成更稳定的结构，要么根本不形成。候选材料中更稳定的形式是否为TI，还有待确定。然而，TI发现计算通常不会评估预测为TI的假定结构形式是否也是这些化合物的稳定形式。在这里，我们证明了在广泛的III-BiO_3氧化物(III=Al，Ga，In，Sc，Y和La)中，立方的ABiO_3钙钛矿结构是不稳定的，而稳定的ABiO_3结构形式是平凡的带状绝缘体。
The quest for broadening the materials base of topological insulators (TIs) beyond the handful of presently known examples has recently led to exploratory calculations of the topological Z2 metric from the band structure of various candidate compounds in assumed crystal structures. However, structural transformations such as volume compression, lattice straining, or atom swaps that are used to instigate in a trivial insulator the band inversion underlying TI-ness, might also destabilize the system to the point that it either distorts into a more stable structure or does not form at all. Whether the more stable form of the candidate material is a TI, it is to be determined. Yet, often TI discovery calculations do not assess whether the postulated structural forms predicted to be TIs are also the stable forms of these compounds. Here, we show that in the broad family of III-Bi-O3 oxides (III = Al, Ga, In, Sc, Y, and La), the cubic ABiO3 perovskite structure, which has been recently predicted to be TI for YBiO3, is unstable, whereas the stable ABiO3 structural forms are trivial band insulators.