Gated, asymmetric rings as tunable electron interferometers

We have fabricated gated, asymmetric rings which, in principle, enable interference between electron waves to be varied with a gate voltage. Although close to the minimum dimensions currently achievable, the results are far from clear-cut, and imply that there are many problems to be overcome before useful devices based on quantum interference can be demonstrated, even supposing that the geometries proposed will actually work. We describe the methods used to analyse our data to show any consistent interference effects caused by the gate voltage variation. Narrower, higher-mobility devices are required in order to produce more easily-resolved gate voltage-controlled interference effects. © 1990.