Theoretical Analysis of Conductance of Molecular Junctions

摘要

The underlying motivation of this project is a fresh look at the theoretical description of electron transport across molecular junctions. In contrast to the current method which is based on the formalism of non- equilibrium Green's function, we treat transport as a dynamical problem in the framework of time-dependent density functional theory (TDDFT). The advantage of our alternative approach is an explicit, more physical description of conductance which is not restricted to linear response and ground-state properties. Our goal is to formulate a benchmark problem for which the theoretical conductance can be unambiguously established, thus elucidating the mechanisms of charge flow across junction-electrode contact, as well as allowing new interpretations of conductance switching behavior that have been observed. Although the project started on May 30, 2002, actual research did not begin until 9 months later because of personnel availability, the Co-Pi moved from MIT to OSU in September 2002, the Research Assistant, a graduate student in the Department of Nuclear Science and Engineering, was not appointed on January 15, 2003, and a Postdoctoral Associate joined the project on June 1, 2003. Presently operating under a no-cost extension, the project is scheduled to end on February 16, 2006.