We propose that a pair of organic molecules can mimic the behavior of a macroscopic fuse at nanoscale, one component of the pair being the $\mathit{on}$ state and the other the off state. For this task we make use of density-functional theory to calculate the physical properties of selected molecules, which have also been synthesized by our team. By this means we obtain the transmission spectra and the current of the proposed devices, which allows us to compare the behavior of the $\mathit{on}$ and off states. Of particular interest is the on/off switch ratios, defined as the current ratios of the $\mathit{on}$ and off structures at the corresponding bias voltage. In a first stage, we examine the best linker between the device and the electrode for high on/off switch ratios. Once this is determined, we test the influence of the electron richness of the system to provide a high on/off switch ratio. The entire analysis is also supported by the molecular projected self-consistent Hamiltonian, which provides a good way of understanding the molecular behavior. All the calculations support that interesting on/off switch ratios of two orders of magnitude could be obtained with these prototypical nanofuses.

• Received 20 August 2010

DOI:https://doi.org/10.1103/PhysRevB.83.125424