A novel superconducting glass state in disordered thin films in Clogston limit

A theory of mesoscopic fluctuations in disordered thin superconducting films in a parallel magnetic field is developed. At zero temperature and at a sufficiently strong magnetic field, the superconducting state undergoes a phase transition into a state characterized by superfluid densities of random signs, instead of a spin polarized disordered Fermi liquid phase. Consequently, in this regime, random supercurrents are spontaneously created in the ground state of the system, which belongs to the same universality class as the two dimensional XY spin glass. As the magnetic field increases further, mesoscopic pairing states are nucleated in an otherwise homogeneous spin polarized disordered Fermi liquid. The statistics of these pairing states is universal depending on the sheet conductance of the 2D film. Suggested PACS index category: 05.20-y, 82.20-w Typeset using REVTEX 1