LOW-ENERGY EXCITATIONS AND NONERGODICITY IN THE COULOMB GLASS

Recent computational methods permit the determination of the low energy states of fair sized systems of localized interacting particles in random media. Making use of such methods, this paper evaluates the nature of the low-energy excitations of the system, and it's implications on conductivity and on ergodicity. Two- and three-dimensional systems are examined. it is found that the low energy excitations exhibit strong correlation effects, indicating that one-particle theories for equilibrium and non-equilibrium properties are not justified. Ergodicity is tested by relaxation at zero temperature. It is found that relaxation time can be extremely long, indicating that the system is not ergodic at low temperatures.