Electron Glass

A glass is a system that does not reach thermodynamic equilibrium during any reasonable experimental time. Therefore, the traditional well established statistical mechanics methods cannot be applied to such systems. Despite being one of the important phases of matter its understanding is still very vague.  Phenomena such as slow relaxation to equilibrium, memory effects and aging have been for many years among some of the major unsolved problems of statistical and condensed-matter Physics. In recent years, experiments showed that the electric conductivity in highly disordered electronic systems exhibits glassy phenomena such as slow relaxation to equilibrium, memory effects and aging. These effects result from a combination of disorder and electronic interactions. Since the conducting electrons are responsible for the glassy behavior these systems were termed “Electron Glasses”. In most experimental systems the relaxation has been found to be independent of temperature and thus these systems have been identified as a special case of a “quantum glass” in which the basic transition that determine the system relaxation to equilibrium are dominated by tunneling rather than by thermal activations over barriers.