Jm. Martinis et al., Calculation of T-c in a normal-superconductor bilayer using the microscopic-based Usadel theory, NUCL INST A, 444(1-2), 2000, pp. 23-27
The Usadel equations give a theory of superconductivity, valid in the diffu
sive limit, that is a generalization of the microscopic equations of the BC
S theory. Because the theory is expressed in a tractable and physical form,
even experimentalists can analytically and numerically calculate detailed
properties of superconductors in physically relevant geometries. Here, we d
escribe the Usadel equations and review their solution in the case of predi
cting the transition eeo temperature T-C of a thin normal-superconductor bi
layer. We also extend this calculation for thicker bilayers to show the dep
endence on the resistivity of the films. These results, which show a depend
ence on both the interface resistance and heat capacity of the films, provi
de important guidance on fabricating bilayers with reproducible transition
temperatures. Published by Elsevier Science B.V.