Conductance Fluctuations in Disordered Sub-Micron Wires and Rings

Abstract

A review of the many of the unexpected experimental results obtained over the last three years on the low temperature quantum transport properties of sub-micron normal metal samples is presented. Measurements can now be made on devices where the lithographically patterned distances between measurements probes is much smaller the the characteristic distances over which the conduction electrons maintain their quantum mechanical phase coherence. This in turn has permitted the discoveries of many new quantum interference effects such as the Aharonov-Bohm effect in highly disordered conductors, universal conductance fluctuations, and non-local quantum effects. The ability to vary both the temperature and sample size has yielded information on the effects of averaging these quantum effects over uncorrelated regions and has shown us to some extent how the transition from quantum to a classical system is achieved.