Fractional-flux oscillations of Josephson critical currents in multi-gap superconductors: a test for unconventional superconductivity

M. Donaire; A. Cano

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arXiv · 2502.09964

Fractional-flux oscillations of Josephson critical currents in multi-gap superconductors: a test for unconventional superconductivity

M. Donaire·A. Cano

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Abstract

Josephson-junction interferometry has played a pivotal role in uncovering unconventional superconductivity in the cuprates. Using a Ginzburg-Landau-like approach, we generalize previous results to the genuine multi-gap case. Thus, we show that fractional flux oscillations of the Josephson critical current can arise as a direct consequence of multi-gap superconductivity. These oscillations reveal key information about the underlying superconducting states, including the unconventional $s_\pm$-wave state. Thus, our findings suggest new phase-sensitive experiments to characterize the Cooper pairing of new emerging superconductors such as the nickelates.

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M. Donaire, A. Cano. 2025-02-14. Fractional-flux oscillations of Josephson critical currents in multi-gap superconductors: a test for unconventional superconductivity. https://arxiv.org/abs/2502.09964

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