Renormalization-group study of gate charge effects in Josephson-junction chains

M. Y. Choi; Sung Wu Rhee; Minchul Lee; J. Choi

doi:10.1103/PhysRevB.63.094516

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Renormalization-group study of gate charge effects in Josephson-junction chains

M. Y. Choi, Sung Wu Rhee, Minchul Lee, J. Choi

DOI 10.1103/PhysRevB.63.094516 · Physical Review B

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Abstract

We study the quantum phase transition in a chain of superconducting grains, coupled by Josephson junctions, with emphasis on the effects of gate charges induced on the grains. At zero temperature the system is mapped onto a two-dimensional classical Coulomb gas, where the gate charge plays the role of an imaginary electric field. Such a field is found relevant in the renormalization-group transformation and to change the nature of the superconductor-insulator transition present in the system, tending to suppress quantum fluctuations and helping establish superconductivity. On the basis of this observation, we propose the zero-temperature phase diagram on the plane of the gate charge and the energy ratio.