Aharonov-Bohm effect in a side-gated graphene ring

TL;DR

This study demonstrates control over Aharonov-Bohm oscillations in a graphene ring via side and back gating, revealing phase jumps and coherence properties at low temperatures.

Contribution

It reports the first observation of gate-tunable phase jumps in Aharonov-Bohm oscillations in a graphene ring structure.

Findings

Aharonov-Bohm oscillations with 5% visibility observed

Phase jumps of pi induced by gate voltage changes

Phase coherence length around 1 micrometer at 500mK

Abstract

We investigate the magnetoresistance of a side-gated ring structure etched out of single-layer graphene. We observe Aharonov-Bohm oscillations with about 5% visibility. We are able to change the relative phases of the wave functions in the interfering paths and induce phase jumps of pi in the Aharonov-Bohm oscillations by changing the voltage applied to the side gate or the back gate. The observed data can be well interpreted within existing models for 'dirty metals' giving a phase coherence length of the order of 1 micrometer at a temperature of 500mK.