Investigation of the Mesoscopic Aharonov-Bohm effect in Low Magnetic Fields

TL;DR

This study explores the mesoscopic Aharonov-Bohm effect in semiconductor rings at low magnetic fields, revealing phase shifts and period halving in conductance oscillations, consistent with theoretical models involving arm asymmetry.

Contribution

It provides experimental evidence of phase shifts and period halving in Aharonov-Bohm oscillations, supported by a theoretical model accounting for arm asymmetry.

Findings

Observation of $$ phase shifts in oscillations

Halving of the $h/e$ period with electron density variation

Agreement between experimental results and theoretical predictions

Abstract

We have investigated the Aharonov-Bohm effect in mesoscopic semiconductor GaAs/GaAlAs rings in low magnetic fields. The oscillatory magnetoconductance of these systems is systematically studied as a function of electron density. We observe phase-shifts of $\pi$ in the magnetoconductance oscillations, and halving of the fundamental $h/e$ period, as the density is varied. Theoretically we find agreement with the experiment, by introducing an asymmetry between the two arms of the ring.