Conductance fluctuations and distribution in disordered chains in the presence of an electric field

A simple Kronig-Penney model for ID mesoscopic systems with disordered δ-peak and finite width potentials is used to study numerically the influence of a constant electric field on the conductance fluctuations and probability distribution. The electric field applied to such systems allows us to obtain the insulating, transition and metallic regimes. The results are globally in agreement with the previous works on quasi-1D and higher dimensions. However, the following new behaviors are observed in such systems: (a) For the superlocalisation observed recently in such systems, the conductance fluctuations are very small in comparison to the usual insulating regime. (b) The transition region does not correspond to that expected by Mato and Caro for (E ≃ V). This region is found to be still an insulating one. By increasing the field we find a behavior different from the well-known one in this region. (c) In some regions of the metallic regime the conductance decreases instead of increasing with the field due to the Wannier-Stark ladder localization observed recently in such systems. Further, discussions are given about the effect of the field on the dielectric rupture and also on the insulator-metal transition.