Topological superconductivity in a phase-controlled Josephson junction
Topological superconductivity in a phase-controlled Josephson junction
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DOI：
10.1038/s41586-019-1148-9
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发表时间：
2019-05-02
期刊：
影响因子：
64.8
通讯作者：
Yacoby, Amir
中科院分区：
文献类型：
--
作者：
Ren, Hechen;Pientka, Falko;Yacoby, Amir
拓扑超导体可以在其边界（1-5）下支持局部主要国家。这些准粒子激发遵循可用于以拓扑保护的方式对量子信息进行编码和操纵量子信息的非亚洲统计数据（6,7）。尽管已经在一维系统中观察到了Majorana绑定状态的签名，但仍在不断努力寻找不需要参数的替代平台，并且可以轻松地缩放到大量状态（8-21）。在这里，我们提出了针对Majorana Bound State的二维结构的实验方法。使用由HGTE量子制成的Josephson结，与薄膜铝制耦合，我们能够通过控制整个连接点的相位差并施加平面磁场（22）来调整琐事和拓扑超导状态之间的过渡（22）。我们通过测量连接边缘的隧道电导来确定所得超导体的拓扑状态。在低磁场上，我们观察到与零偏置附近的隧道光谱中的最小值，这与微不足道的超导体一致。但是，随着磁场的增加，隧道电导会发展为零偏置峰，该峰持续在一系列相位差异上，随着磁场的增加而系统地扩展。我们的观察结果与该系统的理论预测以及在具有相似维度和参数的模型系统上执行的完整量子机械数值模拟一致。我们的工作将该系统确立为实现拓扑超导性以及创建和操纵Majorana模式以及二维系统中探索拓扑超导阶段的有前途的平台。
Topological superconductors can support localized Majorana states at their boundaries(1-5). These quasi-particle excitations obey non-Abelian statistics that can be used to encode and manipulate quantum information in a topologically protected manner(6,7). Although signatures of Majorana bound states have been observed in one-dimensional systems, there is an ongoing effort to find alternative platforms that do not require fine-tuning of parameters and can be easily scaled to large numbers of states(8-21). Here we present an experimental approach towards a two-dimensional architecture of Majorana bound states. Using a Josephson junction made of a HgTe quantum well coupled to thin-film aluminium, we are able to tune the transition between a trivial and a topological superconducting state by controlling the phase difference across the junction and applying an in-plane magnetic field(22). We determine the topological state of the resulting superconductor by measuring the tunnelling conductance at the edge of the junction. At low magnetic fields, we observe a minimum in the tunnelling spectra near zero bias, consistent with a trivial superconductor. However, as the magnetic field increases, the tunnelling conductance develops a zero-bias peak, which persists over a range of phase differences that expands systematically with increasing magnetic field. Our observations are consistent with theoretical predictions for this system and with full quantum mechanical numerical simulations performed on model systems with similar dimensions and parameters. Our work establishes this system as a promising platform for realizing topological superconductivity and for creating and manipulating Majorana modes and probing topological superconducting phases in two-dimensional systems.