Differential current noise as an identifier of Andreev bound states that induce nearly quantized conductance plateaus
Differential current noise as an identifier of Andreev bound states that induce nearly quantized conductance plateaus
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DOI：
10.1103/physrevb.108.l121407
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发表时间：
2023-01
影响因子：
3.7
通讯作者：
Zhan-qiang Cao;Gu Zhang;Hao Zhang;Ying Liang;Wan-Xiu He;Keda He;Dong E. Liu
中科院分区：
文献类型：
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作者：
Zhan-qiang Cao;Gu Zhang;Hao Zhang;Ying Liang;Wan-Xiu He;Keda He;Dong E. Liu
量子化电导平台是马约拉纳束缚态(MBS)十年前预测的一个著名标志，最近在铁基超导体和混合纳米线中观察到了微小的偏差。在这里，我们证明了几乎量子化的电导平台也可以由平凡的Andreev束缚态(ABS)产生。为了避免ABS中断，我们建议通过测量相关的微分电流噪声$P$与偏置电压$V$来识别ABS诱导的量化电导平台。具体地说，对于一个或多个低能ABS诱导的量子电导平台，相关的$P(V)$曲线在零偏压附近呈现双峰，峰位置在$e|V|\约3k_B T$(其中$T$是温度)，峰值大于$2e^3/h$。这些特征与MBS或准MBS形成鲜明对比，后者的美元P(V)$曲线显示出广泛的零偏差，并始终低于2e^3/h$。该协议可以在使用电极或STM尖端作为探针的各种MBS候选平台上实际实现。
Quantized conductance plateaus, a celebrated hallmark of Majorana bound states (MBSs) predicted a decade ago, have recently been observed with small deviations in iron-based superconductors and hybrid nanowires. Here, we demonstrate that nearly quantized conductance plateaus can also arise from trivial Andreev bound states (ABSs). To avoid ABS interruptions, we propose identifying ABS-induced quantized conductance plateaus by measuring the associated differential current noise $P$ versus bias voltage $V$. Specifically, for a quantized conductance plateau induced by one or multiple low-energy ABSs, the associated $P(V)$ curve exhibits a double-peak around zero bias, with the peak positions at $e|V|\approx 3k_B T$ (where $T$ is the temperature) and peak values larger than $2e^3/h$. These features greatly contrast those of an MBS or quasi-MBS, whose $P(V)$ curve displays a broad zero-bias dip and is consistently below $2e^3/h$. This protocol can be practically implemented in a variety of MBS candidate platforms using an electrode or STM tip as a probe.