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arXiv · 1008.4513

Universal R-C crossover in current-voltage characteristics for unshunted array of overdamped Nb-AlO_x-Nb Josephson junctions

S. Sergeenkov·V. A. G. Rivera·E. Marega·F. M. Araujo-Moreira
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Abstract

We report on some unusual behavior of the measured current-voltage characteristics (CVC) in artificially prepared two-dimensional unshunted array of overdamped Nb-AlO_x-Nb Josephson junctions. The obtained nonlinear CVC are found to exhibit a pronounced (and practically temperature independent) crossover at some current I_{cr}=\left(\frac{1}{2β_C}-1\right)I_C from a resistance R dominated state with V_R=R\sqrt{I^2-I_C^2} below I_{cr} to a capacitance C dominated state with V_C=\sqrt{\frac{\hbar}{4eC}} \sqrt{I-I_C} above I_{cr}. The origin of the observed behavior is discussed within a single-plaquette approximation assuming the conventional RSJ model with a finite capacitance and the Ambegaokar-Baratoff relation for the critical current of the single junction.

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S. Sergeenkov, V. A. G. Rivera, E. Marega, F. M. Araujo-Moreira. 2010-08-26. Universal R-C crossover in current-voltage characteristics for unshunted array of overdamped Nb-AlO_x-Nb Josephson junctions. https://doi.org/10.1063/1.3407566

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