Conductance enlargement in pico-scale electro-burnt graphene nanojunctions

TL;DR

This study combines theoretical and experimental approaches to understand conductance behavior in electro-burnt graphene nanojunctions, revealing a conductance increase due to quantum interference before gap formation, which signals pico-scale junction creation.

Contribution

It provides new insights into conductance enlargement mechanisms in electro-burnt graphene junctions, highlighting quantum interference effects during nanogap formation.

Findings

Conductance increases just before gap formation due to quantum interference.

The conductance behavior indicates a transition from multi-path to single-path connectivity.

Electro-burnt junctions form pico-scale current paths from a single sp2-bond.

Abstract

Provided the electrical properties of electro-burnt graphene junctions can be understood and controlled, they have the potential to underpin the development of a wide range of future sub-10nm electrical devices. We examine both theoretically and experimentally the electrical conductance of electro-burnt graphene junctions at the last stages of nanogap formation. We account for the appearance of a counterintuitive increase in electrical conductance just before the gap forms. This is a manifestation of room-temperature quantum interference and arises from a combination of the semi-metallic band structure of graphene and a crossover from electrodes with multiple-path connectivity to single-path connectivity just prior to breaking. Therefore our results suggest that conductance enlargement prior to junction rupture is a signal of the formation of electro-burnt junctions, with a pico-scale current path formed from a single sp2-bond.