Colloquium Series

“High Spectral Resolution at the Atomic Scale: Resolving the Unresolved with the STM,” Wilson Ho, University of California at Irvine, hosted by Jeffrey Guest

Absract: One of the joys of instrumentation development is associated with making measurements that arepreviously not possible. While the scanning tunneling microscope (STM) is known for its inherent capability of sub-Angstrom spatial resolution, the extension to other limits of measurement continues to be an interesting challenge. The spectral resolution can be increased by lowering the temperature of the sample and the microscope to below 1 K. Combined with ultrahigh vacuum and high magnetic field, high spectral resolution has enabled the observation of states that would otherwise remain hidden. These hidden states reveal new interactions that are best observed in single molecules. The STM results provide stringent testing grounds for density functional theory and challenge our scientific understanding.