Monte Carlo studies of percolation in a superconducting array

Journal Article · Fri Feb 01 04:00:00 EST 1991 · Physical Review, B: Condensed Matter; (USA)

DOI:https://doi.org/10.1103/PhysRevB.43.3042· OSTI ID:5711249

Zeng, X C ^[1]; Stroud, D ^[2]; Chung, J S ^[3]

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1. The James Franck Institute, The University of Chicago, Chicago, Illinois 60637 (USA)
2. Department of Physics, The Ohio State University, Columbus, Ohio 43210 (USA)
3. Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824 (USA)

We investigate phase transitions in a two-dimensional site-diluted superconducting array, using Monte Carlo simulations. The array is modeled via a site-diluted classical {ital XY} model on a square lattice in the regime {ital p}{sub {ital c}}{lt}{ital p}{lt}1, where {ital p} is the concentration of spins'' (representing the phases of the superconducting order parameters on the grains) and {ital p}{sub {ital c}} denotes the percolation threshold. In the unfrustrated case (zero magnetic field), we find that the Kosterlitz-Thouless (KT) transition temperature {ital T}{sub {ital c}}({ital p}) approaches zero according to the power law {ital T}{sub {ital c}}({ital p}){similar to}({ital p}{minus}{ital p}{sub {ital c}}){sup {kappa}} and {kappa}{approx}1.14, as {ital p}{r arrow}{ital p}{sub {ital c}} from above. To within the accuracy of the calculation, {kappa} equals the expected value of {ital t}, where {ital t}{approx}1.30 is the usual conductivity exponent. In the fully frustrated case, which in a perfect lattice ({ital p}=1) is characterized by a phase transition of combined KT- and Ising-like character, we find no Ising-like character in the diluted lattice. The apparent KT behavior is broadened over a considerable temperature range, compared to the case in the perfect lattice.

• OSTI ID: 5711249
• Journal Information: Physical Review, B: Condensed Matter; (USA), Journal Name: Physical Review, B: Condensed Matter; (USA) Vol. 43:4; ISSN 0163-1829; ISSN PRBMD
• Country of Publication: United States
• Language: English

Related Subjects

656100* -- Condensed Matter Physics-- Superconductivity
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
COMPUTERIZED SIMULATION
JOSEPHSON EFFECT
MONTE CARLO METHOD
SIMULATION
SUPERCONDUCTORS