Measuring the nonlocality of different types of Majorana bound states in a topological superconducting wire
Measuring the nonlocality of different types of Majorana bound states in a topological superconducting wire
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测量拓扑超导线中不同类型马约拉纳束缚态的非定域性
DOI：
10.1088/1361-648x/aaf149
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
Tian Hongyu
中科院分区：
文献类型：
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作者：
Ren Chongdan;Wu Ya;Sun Minglei;Wang Sake;Tian Hongyu
根据拓扑保护程度的不同，马约拉纳束缚态可分为理想零能束缚态、有限能束缚态和宇称交叉点零能束缚态。在这里，我们研究了这三种类型的MBSs的非局域性通过比较正常的铅拓扑超导线正常铅（NSN）结和NS结的电导谱。我们发现，对于FEM相关的隧道过程中，减少非本地过程是平凡的伴随着本地过程的增加，而对于IZM相关的隧道过程中，左，右隧道过程是完全独立的。值得注意的是，PZMs诱导非局部电子阻挡效应，其中来自左引线的入射电子不能参与局部Andreev反射，除非右引线存在，即使在NSN结的右引线中没有发生非局部隧穿过程。我们发现，这种PZM介导的非局域电子阻塞效应是由于非局域耦合的左导致更远的PZM和之间的相位差的两端PZM。我们的研究结果提供了一个实验方法，通过探测它们不同的非本地签名来表征MBS。
According to the degree of topological protection, Majorana bound states (MBSs) can be divided into three types: ideal zero-energy MBSs (IZMs), finite-energy MBSs (FEMs) and zero-energy MBSs at parity crossing points (PZMs). Herein, we investigate the nonlocality of these three types of MBSs by comparing the conductance spectra of a normal lead–topological superconducting wire–normal lead (NSN) junction and an NS junction. We find that for the FEM-related tunnelling process, the decrease in the nonlocal processes is trivially accompanied by an increase in the local processes, whereas for the IZM-related tunnelling process, the left and right tunnelling processes are completely independent. Remarkably, PZMs induce a nonlocal electron-blocking effect in which incoming electrons from the left lead cannot participate in local Andreev reflection unless the right lead is present, even though no nonlocal tunnelling processes occur in the right lead of an NSN junction. We show that this PZM-mediated nonlocal electron-blocking effect is due to the nonlocal coupling of the left lead to the more distant PZM and that the phase difference between the two end PZMs is . Our findings provide an experimentally accessible method for characterizing MBSs by probing their different nonlocal signatures.