Quasiparticle localization transition in dirty superconductors - art. no. 174511

In this paper, a delocalization-localization transition within a supercondu cting state is explored. The symmetries of the Bogoliubov deGennes Hamilton ian endow the two associated superconducting phases-the thermal metal and t he thermal insulator-and the critical point between them, with properties t hat are in stark contrast with analogous phases in normal systems. Here, fo r systems preserving spin-rotational invariance and time-reversal symmetry in three dimensions, the transition is shown to be of a different universal ity class from its normal partner by extracting and comparing the localizat ion length exponent. The density of states, which may be regarded as the "o rder parameter" for the field theory describing the superconducting system, is studied for its unusual properties about criticality.