FLUX-LATTICE MELTING IN LAYERED SUPERCONDUCTORS

We describe a new representation to treat flux-lattice melting in an extreme type-II layered superconductor, generalizing an approach of Hu and MacDonald. The Ginzburg-Landau free-energy functional is expanded in eigenstates which are products of the lowest Landau levels in the xy plane, and tight-binding Bloch states in the z direction. The various correlation functions can be evaluated efficiently by Monte Carlo simulations. The melting temperature for a model of Bi2Sr2CaCu2O8+delta, as estimated from the apparently simultaneous disappearance of Bragg peaks in the density-density correlation function, and of long-range interlayer correlations, is estimated to be about 30 K at a field of 1 T, in reasonable agreement with the experimental value of 26 K.