9705246 Weitering The primary goal of this new research program is to explore the fundamentals of electron localization at crystalline semiconductor surfaces or in ultrathin epitaxial films. The PI who is a junior faculty member at Tennessee will measure the temperature dependence of the surface state conductance and attempt to correlate these classical transport measurements with state densities and band dispersions as measured with angle-resolved photoemission, electron energy loss spectroscopy and scanning tunneling spectroscopy. In addition, we will explore the possible formation of local magnetic moments using the a.c. susceptibility technique in ultrahigh vacuum. It is expected that this multi-technique approach will ultimately bridge the gap between surface science and mesoscopic physics, thereby generating a profound impact on both condensed matter physics and semiconductor technology. %%% The primary goal of this new research program is to explore the fundamentals of electron localization at crystalline semiconductor surfaces or in ultrathin epitaxial films. The trend toward miniaturization of industrial components is leading to materials that are so small as to be nearly two-dimensional. The smaller a sample, the more important its surface properties, simply because the surface represents a higher percentage of the sample. In order to learn something about surfaces, scientists have "bombarded" surfaces with quantum particles such as electrons or photons. Unfortunately, such experiments are extremely difficult to relate to practical matters such as electrical conductance. In this research project, we are exploring new ways to measure the electrical and magnetic properties of semiconductor surfaces and thin films directly. A novel method is being implemented to electrically insulate the surface from the bulk so that we can measure the electrical resistance o f the surface. We are also constructing a very sensitive nstrument capable of detecting extremely weak magnetic signals from a surface. It is expected that these new measurements will provide unprecedented insights that will help to bridge the gap between the physicist's world of atoms and molecules and the engineer's world of device fabrication. ***
