Observation of the Aharonov-Bohm effect forωcτ>1

Abstract

We have observed the Aharonov-Bohm effect in the magnetoresistance of doubly connected geometries fabricated in high-mobility GaAs/AlGaAs heterostructures. Periodic oscillations in the resistance associated with the flux’s penetrating the annulus are suppressed above ${\omega }_c$τ≊5, where ${\omega }_c$ is the cyclotron frequency and τ is the scattering time, while fluctuations in the resistance as a function of magnetic field are observed for 0<${\omega }_c$τ<300, superimposed upon Shubnikov-deHaas oscillations.