Quantum Interferences in Disordered Mesoscopic Insulators.
Résumé
Quantum interferences in disordered mesoscopic insulators is already a quite long story; it begins in 1979 by the observation of Conductance oscillations in a two—dimensional impurity band by M. Pepper [1] . Many experiments have been performed during the eighties up to very recently by the IBM group [2, 3] on Si—MOSFET. It has been shown how reducing sample sizes, one goes from 2D to 1D Variable Range Hopping regime, then from hopping to tunneling at very low temperature. Huge conductance fluctuations versus Fermi energy have been reported in quasi 1D insulating MOSFET’s, and controversaly interpretated as the result either of quantum resonances (T = 0 effect), or of changes of the dominating microscopic resistor for the finite temperature hopping [4]. This means that observed conductance fluctuations can be interpretated either as a quantum phasecoherent mesoscopic effect or as an incoherent mesoscopic effect due to the very dominance of a few classical resistors.