) Virginia Tech., Physics, Robeson Hall 0435, 209-A Robeson Hall, Blacksburg VA 24061, USA
) Using atomic and molecular wires as components in electronic circuits is an appealing idea: such systems can be synthesized with feature lengths smaller than 1 nm, so if we could assemble them onto a chip, as we do today with solid-state transistors, we would gain orders of magnitude in integration levels. In order to advance such a technology, however, several physical issues that have been a major concern for conventional microelectronics need to be addressed at the nanoscale. I will present an overview of recent work in first-principles calculations of electronic transport in nanoscale conductors for which experimental results are available. In particular, I will discuss the transport mechanism in single organic molecules and the role of contact geometry and chemistry to modulate current-voltage characteristics. [1,2] Transistor-like behavior in such molecular devices will also be discussed. [3] Current-induced forces in molecular [4] and atomic [5] wires will be presented to emphasize the role of resonant and off-resonant states in electromigration as well as the contribution of bound states versus scattering states. Effects of ligands and corresponding low-energy vibrational modes on the switching behavior of molecules [6] will exemplify the versatility of molecular structures in molecular electronics applications. Finally, if time permits, shot noise in nanoscale conductors [7] will be discussed to elucidate the role of chemistry and geometry in steady-state current fluctuations. Work supported in part by NSF, Carilion Biomedical Institute and ACS-Petroleum Research Fund.
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