ABSENCE OF LOCALIZATION AND LARGE DC CONDUCTANCE IN RANDOM SUPERLATTICES WITH CORRELATED DISORDER

We study how the influence of structural correlations in disordered sy stems manifests itself in experimentally measurable magnitudes, focusi ng on de conductance of semiconductor superlattices with general poten tial profiles. We show that-the existence of bands of extended states in these structures gives rise to very noticeable peaks in the finite- temperature de conductance as the chemical potential is moved through the bands or as the temperature is increased from zero. On the basis o f these results we discuss how dc conductance measurements can provide information on the location and width of the bands of extended states . Our predictions can be used to demonstrate experimentally that struc tural correlations inhibit the localization effects of disorder.