Topological Dirac semimetal phases in InSb/alpha-Sn semiconductor superlattices
Topological Dirac semimetal phases in InSb/alpha-Sn semiconductor superlattices
复制标题
InSb/α-Sn 半导体超晶格中的拓扑狄拉克半金属相
DOI：
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发表时间：
2016
期刊：
影响因子：
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通讯作者：
Kai Chang
中科院分区：
文献类型：
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作者：
Jian-Peng Sun;Jia-Ji Zhu;Dong Zhang;Kai Chang
我们从理论上证明了Dirac半金属和拓扑绝缘体相共存的InSb/α-Sn常规半导体超晶格，基于先进的第一性原理计算结合低能kp理论。通过适当的界面设计，当生长方向选择为沿着[111]时，会出现较大的界面极化。这种本征极化静电场使带隙大大减小，并最终使能带结构发生反转，导致拓扑Dirac半金属相的出现，在Gamma点附近沿（111）晶向沿着出现一对Dirac节点。在（100）投影面上观察到清晰的表面态和费米弧。此外，我们还发现了一个二维拓扑绝缘体相，具有接近70 meV的大的非平凡带隙，这使得在室温下观察量子自旋霍尔效应成为可能。我们的建议为通过适当的界面设计实现在传统半导体超晶格中共存的拓扑非平凡相铺平了道路。
We demonstrate theoretically the coexistence of Dirac semimetal and topological insulator phases in InSb/alpha-Sn conventional semiconductor superlattices, based on advanced first-principles calculations combined with low-energy kp theory. By proper interfaces designing, a large interface polarization emerges when the growth direction is chosen along [111]. Such an intrinsic polarized electrostatic field reduces band gap largely and.invert the band structure finally, leading to emerge of the topological Dirac semimetal phase with a pair of Dirac nodes appearing along the (111) crystallographic direction near the Gamma point. The surface states and Fermi arc are clearly observed in (100) projected surface. In addition, we also find a two-dimensional topological insulator phase with large nontrivial band gap approaching 70 meV, which make it possible to observe the quantum spin Hall effect at room temperature. Our proposal paves a way to realize topological nontrivial phases coexisted in conventional semiconductor superlattices by proper interface designing.