KOSTERLITZ-THOULESS TRANSITION IN LAYERED HIGH-T(C) SUPERCONDUCTORS

We investigate the Kosterlitz-Thouless (KT) transition in layered high-T(c) superconductors within the framework of the Lawrence-Doniach model, including interlayer Josephson coupling. Our theory is based on the ''iterated mean-field approximation'' of KT, which yields the exact renormalization group (RG) equations in the absence of Josephson coupling. The inclusion of Josephson coupling leads to RG equations that can be solved exactly and exhibit a crossover from two or three dimensions. Numerical results for the critical temperature region in which the KT transition is smeared out are in fair agreement with experimental data.