Nonequilibrium electron charging in carbon-nanotube-based molecular bridges

TL;DR

This paper investigates how electron charging under nonequilibrium conditions affects transport in carbon nanotube molecular bridges, emphasizing the roles of chirality and contact metal type using advanced computational methods.

Contribution

It highlights the importance of self-consistent calculations for semiconducting nanotubes and shows the dependence of charging effects on nanotube chirality and contact metal.

Findings

Charging effects vary with nanotube chirality and contact metal.

Self-consistent methods are crucial for accurate current-voltage predictions in semiconducting nanotubes.

Charging effects are less significant in metallic nanotubes.

Abstract

We evidence the importance of electron charging under nonequilibrium conditions for carbon-nanotube-based molecular bridges, using a self-consistent Green's function method with an extended Huckel Hamiltonian and a three-dimensional Poisson solver. Our analysis demonstrates that such feature is highly dependent on the chirality of the carbon nanotube as well as on the type of the contact metal, conditioning in a nongeneralized way the system's conduction mechanism. Based on its impact on transport, we argue that self-consistency is essential for the current-voltage calculations of semiconducting nanotubes, whereas less significant in the case of metallic ones.