Andreev levels spectroscopy of topological three-terminal junctions
Andreev levels spectroscopy of topological three-terminal junctions
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DOI：
10.1103/physrevb.89.014509
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发表时间：
2013-11
影响因子：
3.7
通讯作者：
S. Valentini;R. Fazio;F. Taddei
中科院分区：
文献类型：
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作者：
S. Valentini;R. Fazio;F. Taddei
我们计算的微分电导探针插入在拓扑约瑟夫森结的弱连接，由半导体纳米线沉积在两个分离的超导体的顶部。我们的目的是了解如何在Andreev束缚态的频谱中的特殊功能，产生由于存在的Majorana束缚态在两端的两个拓扑超导导线定义的结，可以通过测量的微分电导确定。我们发现，当探针允许一个单一的传播模式，微分电导呈现出一个下降，在零电压的零电导接近的位置，在那里的频谱表现出拓扑保护交叉。这可以被看作是马约拉纳态存在的标志，它不需要费米子宇称守恒，并且对参数的变化以及无序是鲁棒的。相反，当探针允许两个或两个以上的传播模式的微分电导类似的安德烈耶夫束缚态的光谱。这是利用数值和分析方法建立的。
We calculate the differential conductance at a probe inserted in the weak link of a topological Josephson junction, consisting of a semiconducting nanowire deposited on top of two separated superconductors. Our aim is to understand how the peculiar features in the spectrum of Andreev bound states, arising due to the presence of Majorana bound states at the ends of the two topological superconducting wires defining the junction, can be determined through a measurement of the differential conductance. We find that when the probe allows a single propagating mode, the differential conductance presents a dip at zero voltage of zero conductance close to the position where the spectrum exhibits the topologically protected crossing. This can be viewed as a signature of the presence of Majorana states, which does not require fermion parity conservation and is robust against parameters' changes, as well as disorder. On the contrary, when the probe allows two or more propagating modes the differential conductance resembles the spectrum of Andreev bound states. This has been established making use of both numerical and analytical methods.