One key element to realize nanoscale electronics is the ability to manipulate in a controlled way the conductance of single molecules. Azobenzene, which undergoes a trans-cis isomerization transition upon irradiation, offers the possibility to realize a conformational, light-driven molecular switch. It is thus crucial to clarify the electrical transport characteristics of this molecule. Here, we investigate theoretically charge transport in a system consisting of carbon nanotubes (CNTs) acting as electrodes which are bridged by cis/trans azobenzene. In clear contrast to Au-electrodes, CNTs can act as true nanoscale electrodes, inducing a strong chirality-dependent renormalization of electronic states near the Fermi level. The low energy conduction properties may thus be dramatically modified by changing the molecule-CNT contact topology and/or the tubes chirality. We propose some possible experimental ways to realize a controlled electrical switching with CNT electrodes.
[1] M. del Valle, R. Gutierrez-Laliga, C. Tejedor, and G. Cuniberti, Nature Nanotechnology 2, 176 (2007); arXiv:0705.0527v1