Andreev spectrum and supercurrents in nanowire-based SNS junctions containing Majorana bound states.
Andreev spectrum and supercurrents in nanowire-based SNS junctions containing Majorana bound states.
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DOI：
10.3762/bjnano.9.127
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发表时间：
2018
影响因子：
3.1
通讯作者：
Aguado R
中科院分区：
文献类型：
--
作者：
Cayao J;Black-Schaffer AM;Prada E;Aguado R
具有Rashba自旋轨道耦合的混合超导-半导体纳米线可以说是在工程拓扑超导体中搜索Majorana束缚态（MBS）的领先平台。我们进行了系统的数值研究的低能量Andreev谱和超导电流在短和长的超导-正常-超导结制成的纳米线与强大的Rashba自旋轨道耦合，其中外部塞曼场施加垂直于自旋轨道轴。特别是，我们调查的Andreev束缚态的详细演变从平凡的拓扑阶段和它们的关系与MBSs的出现。由于有限的长度，系统托管四个MBS，两个在结的内部，两个在外部。它们杂化并在超导相位差为π时产生有限的能量分裂，这是一个非常明显的效应，可以追溯到塞曼场的能谱演化：从Andreev束缚态的平凡相到MBS的拓扑相。同样，我们进行了详细的研究，从平凡的拓扑阶段的短和长结的超电流。根据Andreev谱计算的超电流在平凡相和拓扑相中都是2π周期的。在后者中，当能量分裂可以忽略时，在相位差为π时，它表现出清晰的超导曲线，表明电流-相位曲线对超导区域长度的强烈依赖性。本文还讨论了温度、标量无序和法向透射率的降低对超电流的影响。此外，我们确定个人的贡献MBS。在短结的MBS确定的电流-相位曲线，而在长结的频谱以上的差距（准连续）介绍了一个重要的贡献。
Hybrid superconductor–semiconductor nanowires with Rashba spin–orbit coupling are arguably becoming the leading platform for the search of Majorana bound states (MBSs) in engineered topological superconductors. We perform a systematic numerical study of the low-energy Andreev spectrum and supercurrents in short and long superconductor–normal–superconductor junctions made of nanowires with strong Rashba spin–orbit coupling, where an external Zeeman field is applied perpendicular to the spin–orbit axis. In particular, we investigate the detailed evolution of the Andreev bound states from the trivial into the topological phase and their relation with the emergence of MBSs. Due to the finite length, the system hosts four MBSs, two at the inner part of the junction and two at the outer one. They hybridize and give rise to a finite energy splitting at a superconducting phase difference of π, a well-visible effect that can be traced back to the evolution of the energy spectrum with the Zeeman field: from the trivial phase with Andreev bound states into the topological phase with MBSs. Similarly, we carry out a detailed study of supercurrents for short and long junctions from the trivial to the topological phases. The supercurrent, calculated from the Andreev spectrum, is 2π-periodic in the trivial and topological phases. In the latter it exhibits a clear sawtooth profile at a phase difference of π when the energy splitting is negligible, signalling a strong dependence of current–phase curves on the length of the superconducting regions. Effects of temperature, scalar disorder and reduction of normal transmission on supercurrents are also discussed. Further, we identify the individual contribution of MBSs. In short junctions the MBSs determine the current–phase curves, while in long junctions the spectrum above the gap (quasi-continuum) introduces an important contribution.
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影响因子：
3.7
作者：
Governale, M;Zülicke, U
通讯作者：
Zülicke, U
影响因子：
3.7
作者：
Alicea, Jason
通讯作者：
Alicea, Jason
影响因子：
3.7
作者：
Awoga, Oladunjoye A.;Bjornson, Kristofer;Black-Schaffer, Annica M.
通讯作者：
Black-Schaffer, Annica M.
影响因子：
38.3
作者：
Chang, W.;Albrecht, S. M.;Marcus, C. M.
通讯作者：
Marcus, C. M.
影响因子：
10.8
作者：
Deng, M. T.;Yu, C. L.;Xu, H. Q.
通讯作者：
Xu, H. Q.