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Reflectionless Tunneling Through a Double-Barrier NS Junction

J. A. Melsen·C. W. J. Beenakker
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Abstract

The resistance is computed of an ${\rm NI}_{1}{\rm NI}_{2}{\rm S}$ junction, where N = normal metal, S = superconductor, and ${\rm I}_{i}$ = insulator or tunnel barrier (transmission probability per mode $Γ_{i}$). The ballistic case is considered, as well as the case that the region between the two barriers contains disorder (mean free path $l$, barrier separation $L$). It is found that the resistance at fixed $Γ_{2}$ shows a {\em minimum} as a function of $Γ_{1}$, when $Γ_{1}\approx\sqrt{2}Γ_{2}$, provided $l\gtrsimΓ_2 L$. The minimum is explained in terms of the appearance of transmission eigenvalues close to one, analogous to the ``reflectionless tunneling'' through a NIS junction with a disordered normal region. The theory is supported by numerical simulations. ***Submitted to Physica B.***

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J. A. Melsen, C. W. J. Beenakker. 1994-06-07. Reflectionless Tunneling Through a Double-Barrier NS Junction. https://doi.org/10.1016/0921-4526(94)90062-0

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