Towards a graphene-based quantum interference device

Abstract

We propose a new quantum interference device based on a graphene nanoring attached to two leads. A lateral gate voltage applied across the nanoring creates an electric field perpendicular to the current flow and shifts energy levels of the two arms of the ring. A charge carrier being injected from the source at a given energy couples therefore to different states of the arms. Those states can be in or out of phase at the drain, resulting in interference effects, which allow for a fine control of the current between the two leads by the gate voltage. We find also that electron transport depends on the type of edges (zigzag or armchair) of the nanoring and discuss the effects of edge imperfections on the performance of the quantum interference device.