Josephson-junction thermodynamics and the superconducting phase transition in a SQUID device

Journal Article · Tue Apr 01 04:00:00 EST 1997 · Physical Review, B: Condensed Matter

DOI:https://doi.org/10.1103/PhysRevB.55.R8697· OSTI ID:541961

van den Brink, A M ^[1]; Dekker, H ^[1]

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1. Institute for Theoretical Physics, University of Amsterdam, Valckenierstraat 65, 1018 XE Amsterdam (The Netherlands)

In a model of two ideal BCS superconductors coupled by a tunneling Hamiltonian the nonvanishing of the Josephson internal energy (and entropy) for T{r_arrow}T{sub c}{sup {minus}} is shown to be a consequence of superconducting correlations, which persist in the thermodynamic limit even in the mean-field approximation. The ensuing rapid increase of the Josephson free energy as the temperature of a tunneling junction drops below the superconducting bulk transition temperature T{sub c} makes this transition of first order whenever the phase difference across the junction is fixed to a nonzero value. Taking this into account results in an availability potential governing the nonequilibrium thermodynamics of the junction which, in contrast with previously published results, has no unphysical features like latent heat released upon entering (or a superconducting phase dependent value in) the normal state. The analysis {ital inter alia} predicts a lowering of the critical temperature (to T{sub c}{sup {prime}}) for the junction, which has meanwhile been observed in high-quality superconducting quantum interference devices. {copyright} {ital 1997} {ital The American Physical Society}

• OSTI ID: 541961
• Journal Information: Physical Review, B: Condensed Matter, Journal Name: Physical Review, B: Condensed Matter Journal Issue: 14 Vol. 55; ISSN PRBMDO; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
BCS THEORY
JOSEPHSON JUNCTIONS
MAGNETIC FLUX
PHASE TRANSFORMATIONS
SQUID DEVICES
TEMPERATURE DEPENDENCE
THERMODYNAMICS
TRANSITION TEMPERATURE