Phase Diagram and Level Statistics in D Class Disordered Superconductors

Abstract

Metal-insulator transition and level statistics for the symmetry class D of random matrix ensembles are investigated. That class arises in models of non-interacting quasiparticles in disordered superconductors without time-reversal and spin-rotation invariance. In the metallic regime the nearest neighbor spacing distribution (NNSD) reproduces exactly the Wigner surmise for GUE as one should expect in the presence of magnetic field, whereas in the localized regime, level repulsion is supressed. NNSD reflects therefore some basic symmetries of the system while ignoring particle-hole symmetries.