Channel Interference in a Quasiballistic Aharonov-Bohm Experiment

Abstract

New experiments are presented on the transmission of electron waves through a two-dimensional electron gas ring with a gate on top of one of the branches. Magnetoconductance oscillations are observed, and the phase of the Aharonov-Bohm signal alternates between $0$ and $\pi$ as the gate voltage is scanned. A Fourier transform of the data reveals a dominant period in the voltage, interpreted as the energy spacing between successive transverse modes. A theoretical model including random phase shifts between successive modes reproduces the essential features of the experiment.