Signatures of coherent electron transport in open quantum dot arrays

We discuss the results of experimental studies of coherent electron transport in open quantum dot arrays. These studies suggest that the details of this transport remain highly phase coherent over much of the array, allowing features associated with the quantum mechanical coupling of the dots to be observed. Studies of magneto-conductance oscillations in the arrays appear to show the influence of this coupling through a change in frequency content as their gate voltage is varied. We speculate that this change arises as the contribution to interference of long orbits is suppressed by reducing the strength of the inter-dot coupling. Temperature-dependent studies of these devices reveal evidence for an unexpected `metal-insulator' transition, which is manifest as a logarithmic variation of the conductance at low temperatures, whose sign can correspond to either metallic or insulating behaviour. It is speculated that this logarithmic term provides a novel signature of electron-interaction effects in confined nanostructure devices.