Robust low-energy Andreev bound states in semiconductor-superconductor structures: Importance of partial separation of component Majorana bound states
Robust low-energy Andreev bound states in semiconductor-superconductor structures: Importance of partial separation of component Majorana bound states
复制标题
半导体超导体结构中鲁棒的低能安德烈夫束缚态：马约拉纳束缚态部分分离的重要性
DOI：
10.1103/physrevb.100.155429
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发表时间：
2018
影响因子：
3.7
通讯作者：
S. Tewari
中科院分区：
文献类型：
--
作者：
T. Stanescu;S. Tewari
在超导体-超导体异质结构中，由位置相关的有效势诱导的稳定的拓扑平凡的低能Andreev束缚态（ABS）最近受到了新的关注，因为最近的一系列实验观察到了稳定的量子化零偏压电导平台。我们澄清的机制，形成这样的国家在SM-SC混合纳米线的应用程序下的平行磁场。具体地说，我们证明了：（1）分量Majorana束缚态波函数的部分空间分离对于拓扑平凡的近零能量束缚态的产生和鲁棒性是至关重要的;（2）这种部分空间分离可以由单调光滑的禁闭势或非单调的谷势或山势诱导，其可以由电势门或由位置相关的功函数差引起，（3）分量MBS的自旋极化的符号可以相同或相反，这取决于引起电势的分布，（4）这些自旋极化在产生与局部探针的极大不同的耦合强度和/或确保近零能量ABS的鲁棒性方面不起基本作用，因此，与最近的理论工作中的声明相反，（参考文献[51]）（5）在拓扑平凡状态下测量的高度为2e^2/h的鲁棒、量化、零偏压电导平台必然需要部分分离的ABS（ps-ABS），与自旋极化的相对符号无关。
Robust topologically-trivial low-energy Andreev bound states (ABSs) induced by position-dependent effective potentials have recently come under renewed focus in light of a remarkable set of recent experiments observing robust quantized zero bias conductance plateaus in semiconductor-superconductor (SM-SC) heterostructures. We clarify the mechanisms for the formation of such states in SM-SC hybrid nanowires under the application of a parallel magnetic field. Specifically, we show that, (1) the partial spatial separation of the wave functions of the component Majorana bound states (MBSs) is crucial for the creation and robustness of topologically trivial near-zero-energy ABSs, (2) this partial separation can be induced by monotonic smooth confinement potentials or by non-monotonic valley or hill potentials, which can be induced by potential gates or by a position-dependent work function difference, (3) the signs of the spin polarizations of the component MBSs can be either the same or opposite, depending on the profile of the inducing potential, (4) these spin polarizations do not play a fundamental role in generating vastly different coupling strengths to local probes and/or ensuring the robustness of the near-zero-energy ABS, and hence, in contrast to the claims in a recent theoretical work (Ref. [51]) (5) a robust, quantized, zero bias conductance plateau of height 2e^2/h measured in the topologically trivial regime necessarily requires partially separated ABSs (ps-ABSs), independent of the relative signs of the spin-polarizations.
影响因子：
8.6
作者：
Bagrets, Dmitry;Altland, Alexander
通讯作者：
Altland, Alexander