A study on the tunneling spectroscopy of an N − p S ?> junction and an N − h S ?> junction
A study on the tunneling spectroscopy of an N − p S ?> junction and an N − h S ?> junction
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DOI：
10.1088/1367-2630/16/9/093004
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发表时间：
2014-02
影响因子：
3.3
通讯作者：
Zhongbo Yan;S. Wan
中科院分区：
文献类型：
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作者：
Zhongbo Yan;S. Wan
本文用Blonder-Tinkham-Klip wijk方法研究了正常金属/p波超导结(N−p S)和正常金属/异质结(N−h S)的全隧道谱。我们发现，对于具有非平凡拓扑的p波超导体，存在一个稳定的量子化零偏压电导峰，而对于具有非平凡拓扑结构的异质结构超导体，出现的零偏置电导峰是非量子化的，并且通常与量子化值有相当大的差距。此外，后者对参数特别是自旋-轨道耦合和S波对位势非常敏感。我们对N−h S结的所有结果表明，在电流隧穿实验中，观察到一个小的零偏压电导峰，而不是量子化的零偏压电导峰，这是一个自然的结果。根据实验参数，我们发现，只有改变自旋-轨道耦合的强度，使之比已报道的小几倍，才能使零偏置电导峰与已报道的一样小。此外，我们得到的结果表明，无论是自旋-轨道耦合较强的超导体，还是对偶势相对较弱的邻近S波超导体，都可以产生一个更显著的零偏置电导峰(与实验相比)，甚至是几乎量子化的电导峰。由于S波超导体在自然界中很常见，这一预测可以用目前的实验来验证。
We study the complete tunneling spectroscopy of a normal metal/p-wave superconductor junction ( N − p S ?> ) and a normal metal/heterostructure superconductor junction ( N − h S ?> ), using the Blonder–Tinkham–Klapwijk (BTK) method. We find that, for a p-wave superconductor with non-trivial topology, there exists a stable quantized zero-bias conductance peak, and for heterostructure superconductors with non-trivial topology, the emerging zero-bias conductance peak is non-quantized and usually has a considerable gap to the quantized value. Furthermore, the latter is sensitive to parameters, especially to spin–orbit coupling and the s-wave pairing potential. All results of the N − h S ?> junction we obtained suggest that the observation of a small zero-bias conductance peak, instead of a quantized zero-bias conductance peak, in current tunneling experiments is a natural result. Based on the experiments’ parameters, we find that only by varying the strength of the spin–orbit coupling to be several times smaller than the reported one, can the zero–bias conductance peak be as small as the reported one. Furthermore, the results we obtained suggest that both a stronger spin–orbit coupling and proximity s-wave superconductor with a relatively weaker pairing potential can produce a much more striking zero-bias conductance peak (compared to the experiments), even an almost quantized one. As s-wave superconductors are common in nature, this prediction can be verified using current experiments.