Coherent Flux Tunneling Through NbN Nanowires

• Main Authors: Peltonen, J. T, Astafiev, O. V, Korneeva, Yu. P, Voronov, B. M, Korneev, A. A, Charaev, I. M, Semenov, A. V, Golt'sman, G. N, Ioffe, L. B, Klapwijk, T. M, Tsai, J. S
• Format: Journal Article
• Language: English
• Published: 07-11-2013
• Subjects: Physics - Mesoscale and Nanoscale Physics; Physics - Superconductivity
• DOI: 10.48550/arxiv.1305.6692

We demonstrate evidence of coherent magnetic flux tunneling through
superconducting nanowires patterned in a thin highly disordered NbN film. The
phenomenon is revealed as a superposition of flux states in a fully metallic
superconducting loop with the nanowire acting as an effective tunnel barrier
for the magnetic flux, and reproducibly observed in different wires. The flux
superposition achieved in the fully metallic NbN rings proves the universality
of the phenomenon previously reported for InOx. We perform microwave
spectroscopy and study the tunneling amplitude as a function of the wire width,
compare the experimental results with theories, and estimate the parameters for
existing theoretical models.