Topological Phases in InAs_{1-x}Sb_{x}: From Novel Topological Semimetal to Majorana Wire.
Topological Phases in InAs_{1-x}Sb_{x}: From Novel Topological Semimetal to Majorana Wire.
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DOI：
10.1103/physrevlett.117.076403
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发表时间：
2016-02
影响因子：
8.6
通讯作者：
G. Winkler;Quansheng Wu;M. Troyer;P. Krogstrup;A. Soluyanov
中科院分区：
文献类型：
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作者：
G. Winkler;Quansheng Wu;M. Troyer;P. Krogstrup;A. Soluyanov
具有强自旋轨道相互作用（SOI）的超导近似一维半导体纳米线是目前实现拓扑量子信息处理最有前途的候选材料。在目前的实验中，SOI主要来自外部场，由有限尺寸效应和外加栅极电压引起。这些器件中的拓扑跃迁依赖于微观细节，这使得缩放到大量器件变得困难，除非使用具有显性本征体积SOI的材料。在这里，我们证明了由某些有序合金InAs_{1-x}Sb_{x}制成的导线具有比原始InSb导线大20倍的自旋分裂。特别是，我们在x=0.5的稳定有序CuPt结构中证明了这一点，该结构具有倒带有序，并实现了在体谱中具有三个简并点的新型拓扑半金属，并产生拓扑表面费米弧。实验上可实现的应变既可以驱动该化合物进入拓扑绝缘体相，也可以恢复正常的带有序，使cupt有序的InAs_{0.5}Sb_{0.5} a半导体具有较大的k块自旋分裂的本禀线性。
Superconductor proximitized one-dimensional semiconductor nanowires with strong spin-orbit interaction (SOI) are, at this time, the most promising candidates for the realization of topological quantum information processing. In current experiments the SOI originates predominantly from extrinsic fields, induced by finite size effects and applied gate voltages. The dependence of the topological transition in these devices on microscopic details makes scaling to a large number of devices difficult unless a material with dominant intrinsic bulk SOI is used. Here, we show that wires made of certain ordered alloys InAs_{1-x}Sb_{x} have spin splittings up to 20 times larger than those reached in pristine InSb wires. In particular, we show this for a stable ordered CuPt structure at x=0.5, which has an inverted band ordering and realizes a novel type of a topological semimetal with triple degeneracy points in the bulk spectrum that produce topological surface Fermi arcs. Experimentally achievable strains can either drive this compound into a topological insulator phase or restore the normal band ordering, making the CuPt-ordered InAs_{0.5}Sb_{0.5} a semiconductor with a large intrinsic linear in k bulk spin splitting.