Disorder induced transitions in layered Coulomb gases and superconductors

A 3D layered system of charges with logarithmic interaction parallel to the layers and random dipoles is studied via a novel variational method and an energy rationale which reproduces the known phase diagram for a single lay er. Increasing interlayer coupling leads to successive transitions in which charge rods correlated in N > 1 neighboring layers are nucleated by weaker disorder. For layered superconductors in the limit of only magnetic interl ayer coupling, the method predicts and locates a disorder induced defect-un binding transition in the flux lattice. While N = 1 charges dominate there, N > 1 disorder induced defect rods are predicted for multilayer supercondu ctors.