Phase boundary of superconducting networks: A new approximation scheme

We calculate the normal-superconducting phase boundary of a superconducting wire network in arbitrary magnetic fields using the London approximation of the linearized Ginzburg-Landau equation. Our formulation in terms of the constituent loop currents allows an iteration procedure to calculate the energy of a network, which in turn determines the mean-field transition temperature ${\mathit{T}}_{\mathit{c}}$(H). For infinite lattices, finite-order truncation in this scheme produces good agreement with other calculations and experiments.