REPRODUCIBLE CONDUCTANCE FLUCTUATIONS IN MACROSCOPIC ANDERSON INSULATORS

We study theoretically the reproducible magnetoconductance fluctuations in macroscopic Anderson insulators where complex random interferences yield localization at a scale-xi larger than the elastic mean free path l. Based on the hypothesis of large ergodic quantum fluctuations of xi when a flux quantum is applied through an area-xi-2, we show that the normalized magnetoconductance fluctuation delta-G(tot)/G(tot) is (xi-p(D)/OMEGA-eff)1/2 for ergodic field changes DELTA-B approximately phi-0/xi-2, where xi-p is a percolation correlation length which approaches macroscopic length scales at very low temperatures, and OMEGA-eff is an effective volume for the classical self-averaging of the fluctuations.