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Quantum phase transitions in superconducting arrays under external magnetic fields

Beom Jun Kim·Gun Sang Jeon·M. -S. Choi·M. Y. Choi
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Abstract

We study the zero-temperature phase transitions of two-dimensional superconducting arrays with both the self- and the junction capacitances in the presence of external magnetic fields. We consider two kinds of excitations from the Mott insulating phase: charge-dipole excitations and single-charge excitations, and apply the second-order perturbation theory to find their energies. The resulting phase boundaries are found to depend strongly on the magnetic frustration, which measures the commensurate-incommensurate effects. Comparison of the obtained values with those in recent experiment suggests the possibility that the superconductor-insulator transition observed in experiment may not be of the Berezinskii-Kosterlitz-Thouless type. The system is also transformed to a classical three-dimensional XY model with the magnetic field in the time-direction; this allows the analogy to bulk superconductors, revealing the nature of the phase transitions.

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Beom Jun Kim, Gun Sang Jeon, M. -S. Choi, M. Y. Choi. 1998-10-19. Quantum phase transitions in superconducting arrays under external magnetic fields. https://doi.org/10.1103/physrevb.58.14524

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