Tuning the conductance of a molecular switch

TL;DR

This paper explores how the conductance of a single azobenzene molecule can be controlled via contact topology and nanotube chirality, advancing the development of light-driven molecular switches for nanoscale electronics.

Contribution

It provides a theoretical analysis of charge transport in azobenzene molecules attached to carbon nanotubes, highlighting the influence of contact topology and nanotube chirality on conductance.

Findings

Conductance can be dramatically modified by contact topology.

Nanotube chirality affects the electrical properties of the junction.

Proposes experiments for controlled electrical switching.

Abstract

The ability to control the conductance of single molecules will have a major impact in nanoscale electronics. Azobenzene, a molecule that changes conformation as a result of a trans/cis transition when exposed to radiation, could form the basis of a light-driven molecular switch. It is therefore crucial to clarify the electrical transport characteristics of this molecule. Here, we investigate theoretically charge transport in a system in which a single azobenzene molecule is attached to two carbon nanotubes. In clear contrast to gold electrodes, the nanotubes can act as true nanoscale electrodes and we show that the low-energy conduction properties of the junction may be dramatically modified by changing the topology of the contacts between the nanotubes and the molecules, and/or the chirality of the nanotubes (that is, zigzag or armchair). We propose experiments to demonstrate controlled electrical switching with nanotube electrodes.