Electron Transport Properties of Atomic Carbon Nanowires between Graphene Electrodes

TL;DR

This study investigates electron transport in atomic carbon wires connected to graphene electrodes, revealing robustness of ballistic conductance in longer wires and discovering negative differential resistance in double wires.

Contribution

It provides new insights into the transport properties of atomic carbon wires, especially their robustness against distortions and impurities, and identifies NDR in double wires.

Findings

Ballistic transport in odd-numbered short wires

Robust conductance in longer wires despite distortions

Negative differential resistance in double atomic wires

Abstract

Long, stable and free-standing linear atomic carbon wires have been carved out from graphene recently [Meyer et al: Nature (London) 2008, 454, 319; Jin et al: Phys: Rev: Lett: 2009, 102, 205501]. They can be considered as the extremely narrow graphene nanoribbons or extremely thin carbon nanotubes. It might even be possible to make use of high strength and identical (without charity) carbon wires as a transport channel or on-chip interconnects for field-effect transistors. Here we investigate electron transport properties of linear atomic carbon wire-graphene junctions by nonequilibruim Green's function combined with density functional theory. For short wires, linear ballistic transport is observed in odd-numbered wire but destroyed by Peirerls distortion in even-numbered wire. For wires longer than 2.1 nm as fabricated above, however, the ballistic conductance of carbon wire-graphene junctions is remarkably robust against the Peierls distortion, structural imperfections, and hydrogen impurity adsorption of the linear carbon wires except oxygen impurities. As such, the epoxy groups might be the origin of low conductance experimentally observed in carbon wires. Moreover, double atomic carbon wires exhibit negative differential resistance (NDR) effect.