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arXiv · 2610.05903

Giant nonlinearity of kinetic inductance in superconducting hybrid strip

D. Yu. Vodolazov·Yu. P. Korneeva·M. A. Dryazgov·S. S. Ustavschikov·N. V. Porokhov·N. N. Osipov·I. Yu. Pashenkin·A. A. Korneev·M. A. Tarkhov
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Abstract

We demonstrate giant nonlinearity of the kinetic inductance $L_k$ in a superconducting NbN/Al hybrid strip. In contrast to ordinary superconductors, where the maximum observed current-induced variation of $L_k$ does not exceed tens of percent, we observe a 50-fold change in $L_k$. Physically, this effect is connected with the proximity-induced superconductivity in the Al layer and the specific choice of parameters for which the dependence of the superconducting current $I$ on the Cooper pair momentum $\hbar q$ exhibits a plateau at a current $I^*$ {\it well below} the depairing current. Formally, this leads to $L_k \sim dq/dI \to \infty$ as $I \to I^*$. We believe that our results open a new route for creating the next generation of highly sensitive detectors of electromagnetic radiation, calorimeters, parametric amplifiers, and magnetometers.

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D. Yu. Vodolazov, Yu. P. Korneeva, M. A. Dryazgov, S. S. Ustavschikov, N. V. Porokhov, N. N. Osipov, I. Yu. Pashenkin, A. A. Korneev, M. A. Tarkhov. 2026-10-05. Giant nonlinearity of kinetic inductance in superconducting hybrid strip. https://arxiv.org/abs/2610.05903

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