UNIFIED MODEL FOR 2 LOCALIZATION PROBLEMS - ELECTRON-STATES IN SPIN-DEGENERATE LANDAU-LEVELS AND IN A RANDOM MAGNETIC-FIELD

A single model is presented which represents both of the two apparentl y unrelated localization problems of the title. The phase diagram of t his model is examined using scaling ideas and numerical simulations. I t is argued that the localization length in a spin-degenerate Landau l evel diverges at two distinct energies, with the same critical behavio r as in a spin-split Landau level, and that all states of a charged pa rticle moving in two dimensions, in a random magnetic field with zero average, axe localized.