A scattering formalism is developed for a random potential on a cylinder with flux φ along its axis. Simulations show the possibility of a phase transition in the φ dependence of an ensemble-averaged conductance: The periodicity in φ changes from h/2e to h/e as the potential is weakened. The critical potential decreases as the sample size increases such that the zero-flux conductivity is ∼150$e^2$/h.

• Received 20 October 1986

DOI:https://doi.org/10.1103/PhysRevB.35.423