Rate-equation calculations of the current flow through two-site molecular device and DNA-based junction

Abstract

Here we present the calculations of incoherent current flowing through the two-site molecular device as well as the DNA-based junction within the rate-equation approach. Selected phenomena of interest are discussed in detail. The structural asymmetry of a two-site molecule results in a rectification effect, which can be neutralized by an asymmetric voltage drop at the molecule-metal contacts due to coupling asymmetry. The results received for the poly(dG)-poly(dC) DNA molecule reveal the coupling-and temperature-independent saturation effect of the current at high voltages, establishing for short chains the inverse square distance dependence. Additionally we document the conductance peak shifting in the direction of higher voltages due to a temperature decrease. © Versita Warsaw and Springer-Verlag Berlin Heidelberg 2006.