Voltage-driven quantum oscillations of conductance in graphene

TL;DR

This paper reports voltage-driven quantum conductance oscillations in graphene caused by localized energy states within a gate-induced potential barrier, resembling magnetic oscillations but driven electrically.

Contribution

It introduces a novel quantum transport phenomenon in graphene where conductance oscillates with gate-controlled barrier parameters, driven by localized states outside the Dirac cone.

Findings

Conductance exhibits oscillations as a function of barrier height and width.

Oscillations are caused by singularities in the density of localized states.

Phenomenon resembles Shubnikov-de-Haas oscillations but is electrically driven.

Abstract

Locally-gated single-layer graphene sheets have unusual discrete energy states inside the potential barrier induced by a finite-width gate. These states are localized outside the Dirac cone of continuum states and are responsible for novel quantum transport phenomena. Specifically, the longitudinal (along the barrier) conductance exhibits oscillations as a function of barrier height and/or width, which are both controlled by a nearby gate. The origin of these oscillations can be traced back to singularities in the density of localized states. These graphene conductance-oscillations resemble the Shubnikov-de-Haas (SdH) magneto-oscillations; however, here these are driven by an electric field instead of a magnetic field.