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arXiv · 1410.7689

Dark counts initiated by macroscopic quantum tunneling in NbN superconducting photon detectors

A. Murphy·A. Semenov·A. Korneev·Yu. Korneeva·G. Gol'tsman·A. Bezryadin
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Abstract

We perform measurements of the switching current distributions of three w = 120 nm wide, 4 nm thick NbN superconducting strips which are used for single-photon detectors. These strips are much wider than the diameter the vortex cores, so they are classified as quasi-two-dimensional (quasi-2D). We discover evidence of macroscopic quantum tunneling by observing the saturation of the standard deviation of the switching distributions at temperatures around 2 K. We analyze our results using the Kurkijarvi-Garg model and find that the escape temperature also saturates at low temperatures, confirming that at sufficiently low temperatures, macroscopic quantum tunneling is possible in quasi-2D strips and can contribute to dark counts observed in single photon detectors.

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A. Murphy, A. Semenov, A. Korneev, Yu. Korneeva, G. Gol'tsman, A. Bezryadin. 2014-10-28. Dark counts initiated by macroscopic quantum tunneling in NbN superconducting photon detectors. https://arxiv.org/abs/1410.7689

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