Decoupling and melting in a layered superconductor

We report results for a 3D simulation of a layered superconductor. The low-temperature phase corresponds to a triangular lattice of vortex lines. On increasing the temperature order is lost in the a-b plane, T-ab with no detectable thermodynamic signature. On further increasing the temperature the vortex lines decouple completely at a first-order phase transition, T-dc. The entropy associated with the transition is dependent on the anisotropy chosen for the system and has values of 0.25 kappa(B) and 0.4 kappa(B) for the two anisotropies studied. The width T-dc - T-ab is anisotropy dependent and is too narrow to be measured for the more anisotropic system studied, corresponding to sublimation of the vortices as reported in a recent experiment by Fuchs et al.