Colloquium: Prof. William Schwalm

Prof. William Schwalm
Department of Physics and Astrophysics, University of North Dakota

Minimal models of complicated surface adsorbed structures

Friday, May 9, 2014 4:01pm-4:50pm

With modern techniques, including scanning-tunneling spectroscopy and angle
resolved photoemission, it has become possible to make detailed measurements of local
electronic properties and surface band dispersions. Besides their intrinsic scientific
interest, engineered, possibly self-assembled surface structures might lead into the
ultimate small scale for electronic surface components. But for now one is interested in
using them as tools to explore quantum phenomena.

This presentation will outline an extremely primitive, or extremely simple, model
approximation for quasi one electron properties in complex surface related structures,
such as adsorbed molecules, nanowires or arrays of nanowires and so on. After
describing some techniques, I will focus on local densities of states, spectral densities and
ballistic transport. I expect that the methods will complement the density functional
calculations, as the two approaches have very different strengths. Suggestive,
preliminary results, some published but most unpublished, will show both how the model
works and what kinds of phenomena might be explored. It is hoped that these
techniques will contribute to one or more of the current experimental projects in the
department.