Electronic transport in molecular devices from first principles

Abstract

We present an overview of recent work by the authors in first-principles calculations of electronic transport in molecules for which experimental results are available. We find that the shape of the current-voltage characteristics is mostly determined by the electronic structure of the molecules in the presence of the external voltage whereas the absolute magnitude of the current is determined by the chemistry of individual atoms at the contacts. A three-terminal device has been modeled, showing gain. Current-induced forces have been found to induce collective oscillations of the benzene- 1,4-dithiolate molecule at resonant-tunneling condition. Finally, recent data that show large negative differential resistance and a peak that shifts substantially as a function of temperature have been accounted for.