2 p.m., Thursday, February 6, 2003
Room 1201, Physics Building
Quantum States in Metal Nanoparticles and Single Molecules
Dan Ralph
(Cornell University)
Abstract: I will describe experiments in which we have used
tunneling spectroscopy to measure individual "electron-in-a-box" energy levels
in nanometer-scale metal particles and also quantized states in single
molecules. In metal particles, the level spectra do not correspond to free
electrons, but rather they are modified by the various forces which act on
electrons inside metals. I will describe the different consequences of
spin-orbit coupling, superconducting pairing, magnetic exchange, and magnetic
anisotropy forces. We have also recently succeeded in making single-molecule
transistors within junctions formed by electromigration. These devices exhibit
many of the same phenomena seen in larger-scale devices, such at Coulomb
blockade and the Kondo effect, and they also exhibit new features associated
with the coupling of electron tunneling to molecular motion.