Condensed Matter Physics Seminar

2 p.m., Thursday, May 8, 2003
Room 1201, Physics Building

 Single Molecule Electronics

Stuart Lindsay

(Arizona State)

Abstract:  The contact between a metal or semiconductor surfaces and a molecule is a key issue in the development of molecular electronics because electron transfer is exponentially sensitive to small changes in the bonding arrangement at these interfaces.  In order to explore this problem, we have developed a scheme for making reliable contacts to single molecules.  The ‘test’ molecule is embedded in an inert matrix with one end chemically bonded to a gold surface and the other end chemically bonded to a gold nanoparticle (NP).  The structure is produced by self-assembly, and the top NP contacted by a gold-coated conducting AFM probe.  In this way, we have obtained highly reproducible data from a number of (single) molecules.  First principles simulations give results that are quite close to experiment.  The NP is not a passive participant in the process, and evidence of its electronic structure is seen in measured single-molecule I-V curves.  Somewhat surprisingly, we find that the covalent bond between the molecule and metal is unstable, fluctuating significantly at room temperature to give rise to stochastic “on-off” switching of the wired molecule.
Host:  Fuhrer
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