Tunable Aharonov-Bohm effect in an electron interferometer

Abstract

The Aharonov-Bohm effect has been investigated in submicrometer-sized annuli fabricated from GaAs-${\mathrm{Al}}_{\mathrm{x}}$${\mathrm{Ga}}_{1\mathrm{\ensuremath{-}}\mathrm{x}}$As heterostructures constructed with a narrow metal gate intercepting one branch of the rings. The gate locally alters the phase of the confined electron wave function, making these rings act as tunable electron interferometers. The amplitude and phase of the magnetoresistance oscillations were controlled over a\ensuremath{\approxeq}1 V gate voltage range. Although the device can discriminate between a shift in Feynman trajectories and the electrostatic Aharonov-Bohm effect, no phenomena periodic in gate potential characteristic of the latter were resolved.