Non-local Aharonov-Bohm conductance oscillations in an asymmetric quan-tum ring

TL;DR

This paper reports on the observation of Aharonov-Bohm conductance oscillations in an asymmetric quantum ring, demonstrating ballistic and phase-coherent transport in a nanoscale GaAs/AlGaAs heterostructure device.

Contribution

It reveals equal amplitude AB oscillations in local and non-local measurements due to junction symmetry, a novel finding in asymmetric quantum rings.

Findings

Negative bend resistance indicates ballistic transport

Equal AB oscillation amplitudes in local and non-local setups

Symmetry of junctions influences quantum interference patterns

Abstract

We investigate ballistic transport and quantum interference in a nanoscale quantum wire loop fab-ricated as a GaAs/AlGaAs field-effect heterostructure. Four-terminal measurements of current and voltage characteristics as a function of top gate voltages show negative bend resistance as a clear signature of ballistic transport. In perpendicular magnetic fields phase-coherent transport leads to Aharonov-Bohm (AB) conductance oscillations which show equal amplitudes in the local and the non-local measurement at a temperature of 1.5 K and above. We attribute this novel observation to the symmetry of the orthogonal cross junctions connecting the four quantum wire leads with the asymmetric quantum wire ring.