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Title: Phase and charge re-entrant phase transitions in two capacitively coupled Josephson arrays with ultrasmall junctions

Abstract

We have studied the phase diagram of two capacitively coupled Josephson junction arrays with charging energy, E{sub c}, and Josephson coupling energy, E{sub J}. Our results are obtained using a path integral Quantum Monte Carlo algorithm. The parameter that quantifies the quantum fluctuations in the ith array is defined by {alpha}{sub i}{identical_to}E{sub c{sub i}}/E{sub J{sub i}}. Depending on the value of {alpha}{sub i}, each independent array may be in the semiclassical or in the quantum regime: We find that thermal fluctuations are important when {alpha}{<=}1.5 and the quantum fluctuations dominate when 2.0{<=}{alpha}. Vortices are the dominant excitations in the semiclassical limit, while in the quantum regime the charge excitations are important. We have extensively studied the interplay between vortex and charge dominated individual array phases. The phase diagrams for each array as a function of temperature and interlayer capacitance were determined from results for their helicity modulus, {upsilon}({alpha}), and the inverse dielectric constant, {epsilon}{sup -1}({alpha}). The two arrays are coupled via the capacitance C{sub inter} at each site of the lattices. When one of the arrays is in the quantum regime and the other one is in the semiclassical limit, {upsilon}(T,{alpha}) decreases with T, while {epsilon}{sup -1}(T,{alpha}) increases. This behaviormore » is due to a duality relation between the two arrays: e.g., a manifestation of the gauge invariant capacitive interaction between vortices in the semiclassical array and charges in the quantum array. We find a re-entrant transition in {upsilon}(T,{alpha}), at low temperatures, when one of the arrays is in the semiclassical limit (i.e., {alpha}{sub 1}=0.5) and the quantum array has 2.0{<=}{alpha}{sub 2}{<=}2.5, for the values considered for the interlayer capacitance of C{sub inter}=0.26087, 0.52174, 0.78261, 1.04348, and 1.30435. Similar results were obtained for larger values of {alpha}{sub 2}=4.0 with C{sub inter}=1.04348 and 1.30435. For smaller values of C{sub inter} the superconducting-normal transition was not present. In addition, when 3.0{<=}{alpha}{sub 2}<4.0, and for all the interlayer couplings considered above, a novel re-entrant phase transition occurs in the charge degrees of freedom, i.e., there is a re-entrant insulating-conducting transition at low temperatures. Finally, we obtain the corresponding phase diagrams that have some features that resemble those seen in experiment.« less

Authors:
;  [1]
  1. Instituto de Fisica, Universidad Nacional, Autonoma de Mexico, Apartado Postal 20-364, Mexico 01000, D.F. (Mexico)
Publication Date:
OSTI Identifier:
20664952
Resource Type:
Journal Article
Journal Name:
Physical Review. B, Condensed Matter and Materials Physics
Additional Journal Information:
Journal Volume: 70; Journal Issue: 17; Other Information: DOI: 10.1103/PhysRevB.70.174516; (c) 2004 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 1098-0121
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 36 MATERIALS SCIENCE; ALGORITHMS; CAPACITANCE; COUPLING; DEGREES OF FREEDOM; EXCITATION; FLUCTUATIONS; GAUGE INVARIANCE; JOSEPHSON EFFECT; JOSEPHSON JUNCTIONS; MONTE CARLO METHOD; PATH INTEGRALS; PERMITTIVITY; PHASE DIAGRAMS; PHASE TRANSFORMATIONS; SEMICLASSICAL APPROXIMATION; SUPERCONDUCTORS; TEMPERATURE DEPENDENCE; VORTICES

Citation Formats

Ramirez-Santiago, Guillermo, Jose, Jorge V, and Department of Physics and Center for Interdisciplinary Research on Complex Systems, Northeastern University, 360 Huntington Avenue, Boston, Massachusetts 02115. Phase and charge re-entrant phase transitions in two capacitively coupled Josephson arrays with ultrasmall junctions. United States: N. p., 2004. Web. doi:10.1103/PhysRevB.70.174516.
Ramirez-Santiago, Guillermo, Jose, Jorge V, & Department of Physics and Center for Interdisciplinary Research on Complex Systems, Northeastern University, 360 Huntington Avenue, Boston, Massachusetts 02115. Phase and charge re-entrant phase transitions in two capacitively coupled Josephson arrays with ultrasmall junctions. United States. https://doi.org/10.1103/PhysRevB.70.174516
Ramirez-Santiago, Guillermo, Jose, Jorge V, and Department of Physics and Center for Interdisciplinary Research on Complex Systems, Northeastern University, 360 Huntington Avenue, Boston, Massachusetts 02115. 2004. "Phase and charge re-entrant phase transitions in two capacitively coupled Josephson arrays with ultrasmall junctions". United States. https://doi.org/10.1103/PhysRevB.70.174516.
@article{osti_20664952,
title = {Phase and charge re-entrant phase transitions in two capacitively coupled Josephson arrays with ultrasmall junctions},
author = {Ramirez-Santiago, Guillermo and Jose, Jorge V and Department of Physics and Center for Interdisciplinary Research on Complex Systems, Northeastern University, 360 Huntington Avenue, Boston, Massachusetts 02115},
abstractNote = {We have studied the phase diagram of two capacitively coupled Josephson junction arrays with charging energy, E{sub c}, and Josephson coupling energy, E{sub J}. Our results are obtained using a path integral Quantum Monte Carlo algorithm. The parameter that quantifies the quantum fluctuations in the ith array is defined by {alpha}{sub i}{identical_to}E{sub c{sub i}}/E{sub J{sub i}}. Depending on the value of {alpha}{sub i}, each independent array may be in the semiclassical or in the quantum regime: We find that thermal fluctuations are important when {alpha}{<=}1.5 and the quantum fluctuations dominate when 2.0{<=}{alpha}. Vortices are the dominant excitations in the semiclassical limit, while in the quantum regime the charge excitations are important. We have extensively studied the interplay between vortex and charge dominated individual array phases. The phase diagrams for each array as a function of temperature and interlayer capacitance were determined from results for their helicity modulus, {upsilon}({alpha}), and the inverse dielectric constant, {epsilon}{sup -1}({alpha}). The two arrays are coupled via the capacitance C{sub inter} at each site of the lattices. When one of the arrays is in the quantum regime and the other one is in the semiclassical limit, {upsilon}(T,{alpha}) decreases with T, while {epsilon}{sup -1}(T,{alpha}) increases. This behavior is due to a duality relation between the two arrays: e.g., a manifestation of the gauge invariant capacitive interaction between vortices in the semiclassical array and charges in the quantum array. We find a re-entrant transition in {upsilon}(T,{alpha}), at low temperatures, when one of the arrays is in the semiclassical limit (i.e., {alpha}{sub 1}=0.5) and the quantum array has 2.0{<=}{alpha}{sub 2}{<=}2.5, for the values considered for the interlayer capacitance of C{sub inter}=0.26087, 0.52174, 0.78261, 1.04348, and 1.30435. Similar results were obtained for larger values of {alpha}{sub 2}=4.0 with C{sub inter}=1.04348 and 1.30435. For smaller values of C{sub inter} the superconducting-normal transition was not present. In addition, when 3.0{<=}{alpha}{sub 2}<4.0, and for all the interlayer couplings considered above, a novel re-entrant phase transition occurs in the charge degrees of freedom, i.e., there is a re-entrant insulating-conducting transition at low temperatures. Finally, we obtain the corresponding phase diagrams that have some features that resemble those seen in experiment.},
doi = {10.1103/PhysRevB.70.174516},
url = {https://www.osti.gov/biblio/20664952}, journal = {Physical Review. B, Condensed Matter and Materials Physics},
issn = {1098-0121},
number = 17,
volume = 70,
place = {United States},
year = {Mon Nov 01 00:00:00 EST 2004},
month = {Mon Nov 01 00:00:00 EST 2004}
}