Observation of Quantum Asymmetry in an Aharonov-Bohm Ring

TL;DR

This study experimentally observes quantum asymmetry effects in an Aharonov-Bohm ring, revealing phase shifts and period halving in magnetoconductance oscillations as a function of electron density, supported by theoretical modeling.

Contribution

First systematic experimental investigation of quantum asymmetry effects in Aharonov-Bohm rings with theoretical explanation.

Findings

Observation of $$ phase shifts in oscillations

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

Agreement between experimental results and theoretical asymmetry model

Abstract

We have investigated the Aharonov-Bohm effect in a one-dimensional GaAs/GaAlAs ring at low magnetic fields. The oscillatory magnetoconductance of these systems are for the first time systematically studied as a function of 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.