On the applicability of the layered sine–Gordon model for Josephson-coupled high-Tc layered superconductors

We find a mapping of the layered sine–Gordon model to an equivalent gas of topological excitations and determine the long-range interaction potentials of the topological defects. This enables us to make a detailed comparison to the so-called layered vortex gas, which can be obtained from the layered Ginzburg–Landau model. The layered sine–Gordon model has been proposed in the literature as a candidate field-theoretical model for Josephson-coupled high-Tc superconductors, and the implications of our analysis for the applicability of the layered sine–Gordon model to high-Tc superconductors are discussed. We are led to the conjecture that the layered sine–Gordon and the layered vortex gas models belong to different universality classes. The determination of the critical temperature of the layered sine–Gordon model is based on a renormalization-group analysis.