Critical exponents and fine-grid vortex model of the dynamic vortex Mott transition in superconducting arrays

Enzo Granato

doi:10.1103/PhysRevB.100.104517

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Critical exponents and fine-grid vortex model of the dynamic vortex Mott transition in superconducting arrays

Enzo Granato

DOI 10.1103/PhysRevB.100.104517 · Physical Review B

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Abstract

We study the dynamic vortex Mott transition in two-dimensional superconducting arrays in a magnetic field with f flux quantum per plaquette. The transition is induced by external driving current and thermal fluctuations near rational vortex densities set by the value of f and has been observed experimentally from the scaling behavior of the differential resistivity. Recently, numerical simulations of interacting vortex models have demonstrated this behavior only near fractional f. A fine-grid vortex model is introduced, which allows us to consider both the cases of fractional and integer f. The critical behavior is determined from a scaling analysis of the current-voltage relation and voltage correlations near the transition and by Monte Carlo simulations. The critical exponents for the transition near f=1/2 are consistent with the experimental observations and previous numerical results from a standard vortex model. The same scaling behavior is obtained for f=1, in agreement with experiments. However, the estimated correlation-length exponent indicates that even at integer f, the critical behavior is not of mean-field type.