Tunable multifunctional topological insulators in ternary Heusler compounds
Tunable multifunctional topological insulators in ternary Heusler compounds
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DOI：
10.1038/nmat2770
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发表时间：
2010-07-01
期刊：
影响因子：
41.2
通讯作者：
Zhang, Shou Cheng
中科院分区：
文献类型：
--
作者：
Chadov, Stanislav;Qi, Xiaoliang;Zhang, Shou Cheng
近年来，在基于二元半导体碲化汞的量子威尔斯阱中，量子自旋霍尔效应得到了理论预测和实验实现（参考文献1-3）。量子自旋霍尔态和拓扑绝缘体是基础凝聚态物理和材料科学都感兴趣的量子物质的新状态（1-11）。许多具有C1（B）结构的Heusler化合物是结构和电子上与二元半导体相关的三元半导体。Heusler材料的多样性为调整带隙和通过选择具有适当杂化强度（通过晶格参数）和自旋轨道耦合幅度（通过原子电荷）的化合物来设置所需的带反转提供了广泛的可能性。基于第一性原理计算，我们证明，约50 Heusler化合物显示带反转类似的碲化汞。这些零能隙半导体的拓扑状态可以通过施加应变或设计适当的量子阱结构来创建，类似于碲化汞的情况。这些三元零能隙半导体（LnAuPb、LnPdBi、LnPtSb和LnPtBi）中的许多都含有稀土元素Ln，它可以实现从超导性（例如LaPtBi;参考文献12）到磁性（例如GdPtBi;参考文献13）和重费米子行为（例如YbPtBi;参考文献14）的附加特性。这些性质为实现量子化反常霍尔效应和拓扑超导体开辟了新的研究方向。
Recently the quantum spin Hall effect was theoretically predicted and experimentally realized in quantum wells based on the binary semiconductor HgTe (refs 1-3). The quantum spin Hall state and topological insulators are new states of quantum matter interesting for both fundamental condensed-matter physics and material science(1-11). Many Heusler compounds with C1(b) structure are ternary semiconductors that are structurally and electronically related to the binary semiconductors. The diversity of Heusler materials opens wide possibilities for tuning the bandgap and setting the desired band inversion by choosing compounds with appropriate hybridization strength (by the lattice parameter) and magnitude of spin-orbit coupling (by the atomic charge). Based on first-principle calculations we demonstrate that around 50 Heusler compounds show band inversion similar to that of HgTe. The topological state in these zero-gap semiconductors can be created by applying strain or by designing an appropriate quantum-well structure, similar to the case of HgTe. Many of these ternary zero-gap semiconductors (LnAuPb, LnPdBi, LnPtSb and LnPtBi) contain the rare-earth element Ln, which can realize additional properties ranging from superconductivity (for example LaPtBi; ref. 12) to magnetism (for example GdPtBi; ref. 13) and heavy fermion behaviour (for example YbPtBi; ref. 14). These properties can open new research directions in realizing the quantized anomalous Hall effect and topological superconductors.