Large-scale superconductivity-induced conductance suppression in mesoscopic normal–superconducting structures

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• 作者：Seviour ; R. ; Lambert ; C. J. ; Leadbeater ; M.
• 刊名：Superlattices and Microstructures
• 出版年：1999
• 期刊代码：122_07496036
• 类别：ms
• 出版时间：May, 1999
• 卷：25
• 期：5-6
• 页码：639-645
• 文件大小：110 K

摘要

Experiments on hybrid superconducting normal-metal structures have revealed that even in the absence of tunnel junctions the onset of superconductivity can lead to a decrease in the electrical conductance by an amount many orders of magnitude greater than e²/h. In this paper, we provide a theory of this phenomenon which shows that it originates from an instability in the four-probe conductance which is absent from two-probe measurements. We compare the zero-bias, zero-temperature four-probe conductances G<sub>Nsub>and G<sub>Ssub>of a normal diffusive metal in contact with a superconductor in both the normal (N) and superconducting (S) states, respectively. In the absence of tunnel barriers, the ensemble average of the difference δG