Conductance of a Conjugated Molecule with Carbon Nanotube Contacts

TL;DR

This study models the conductance of a CNT-molecule-CNT system, showing agreement with experiments and highlighting how molecular orbitals and conformations influence electronic transport.

Contribution

It provides a theoretical analysis linking molecular orbital features to conductance in CNT-based junctions, emphasizing the impact of molecular conformation changes.

Findings

Transmission features match molecular orbitals

HOMO conductance is insensitive to end groups and geometry

Conformational changes can increase resistance by over 100 times

Abstract

Calculations of the conductance of a carbon nanotube (CNT)-molecule-CNT structure are in agreement with experimental measurements [1]. The features in the transmission correspond directly to the features of the isolated molecular orbitals. The HOMO provides conductance at low bias that is relatively insensitive to the end groups of the cut CNTs, the cut angle, or the number of molecular bridges. A molecular conformation change not directly in the path of the carrier transport increases the resistance by over 2 orders of magnitude. [1] X. Guo, J. P. Small, J. E. Klare, Y. Wang, M. S. Purewal, I. W. Tam, B. H. Hong, R. Caldwell, L. Huang, S. O'Brien, et al., Science 311, 356 (2006), URL http://www.sciencemag.org/cgi/content/abstract/311/5759/356