Conductance Through Graphene Bends and Polygons

TL;DR

This paper explores how electron transmission in graphene nanoribbons varies with geometry, revealing that specific angles and junction types can significantly enhance or suppress conductance, with detailed tight-binding analysis supporting these findings.

Contribution

It provides new insights into the dependence of electron conductance on geometric configurations in graphene nanoribbons, including effects at various energies and lead types.

Findings

Transmission at low energies is sensitive to junction geometry.

Armchair leads at 120-degree angles can have high or low transmission.

Geometry significantly influences conductance in graphene polygons.

Abstract

We investigate the transmission of electrons between conducting nanoribbon leads oriented at multiples of 60 degrees with respect to one another, connected either directly or through graphene polygons. A mode-matching analysis suggests that the transmission at low-energies is sensitive to the precise way in which the ribbons are joined. Most strikingly, we find that armchair leads forming 120-degree angles can support either a large transmission or a highly suppressed transmission, depending on the specific geometry. Tight-binding calculations demonstrate the effects in detail, and are also used to study transmission at higher energies as well as for zigzag ribbon leads.