Supercooled vortex liquid and quantitative theory of melting of the flux-line lattice in type-II superconductors

Abstract

A metastable homogeneous state exists down to zero temperature in systems of repelling vortices. A zero- "fluctuation-temperature" liquid state therefore serves as a (pseudo) "fixed point" controlling the properties of vortex liquid below and even around melting point. Based on this picture for the vortex phase we apply the Borel-Pade resummation technique to develop a quantitative theory of the vortex liquid for the lowest-Landau-level Ginzburg-Landau model in type-II superconductors. While on the solid phase, there exists a superheat solid phase which ends at the spinodal line. The picture for the vortex phase is supported by an exactly solvable large N Ginzburg-Landau model in a magnetic field and has been recently confirmed by the experiments. The applicability of the lowest-Landau-level model is discussed and corrections due to higher levels are calculated. The melting line is located based on the quantitative theory for the description of the vortex solid and the vortex liquid. Magnetization, entropy, and specific heat jumps along the melting line are calculated. The theoretical results explain quantitatively very well the experimental data on the high-T-c cuprates YBa2Cu3O7, DyBCO, low-T-c material (K, Ba) BiO3, and also Monte Carlo simulation results.