Crossover Between Universality Classes in the Statistics of Rare Events in Disordered Conductors

摘要

The crossover from orthogonal to the unitary universality classes in thedistribution of the anomalously localized states (ALS) in two-dimensionaldisordered conductors is traced as a function of magnetic field. We demonstratethat the microscopic origin of the crossover is the change in the symmetry ofthe underlying disorder configurations, that are responsible for ALS. Thesedisorder configurations are of weak magnitude (compared to the Fermi energy)and of small size (compared to the mean free path). We find their shapeexplicitly by means of the direct optimal fluctuation method.