Surfaces, a Play Ground for Physics in Reduced Dimensionality

                         E. W. Plummer

            Department of Physics and Astronomy, 
                  The University of Tennessee,
                      Knoxville, TN, USA

                              and

                  Oak Ridge National Laboratory, 
                        Oak Ridge, TN, USA

   Surfaces and thin films coupled with new experimental techniques
and growth processes offer a unique platform from which physics in
reduced dimensionality can be investigated.  The scanning tunneling
microscope operated in a variable temperature mode allows us to see
the physical phenomena of interest.  The distinct advantage of the STM
for these studies is that it images the local electronic properties of
the surface.  This lecture will present a visual display of electrons
in two-dimensions, from simple undergraduate quantum mechanics to
current research topics in many-body phenomena.  Images of step edges
show standing wave patterns that can be modeled as a particle and a
hard wall--a beautiful demonstration of quantum mechanics for lower
level physics.  Fourier transform STM will be used to display the
contours of allowed quantum states in E and k (momentum) for different
systems.  Temperature dependent images are utilized to monitor
electronically driven transition such at charge density wave formation
and metal-to-nonmetal transitions.  Finally, observed complex wave
pattern formation will be discussed in the context of many-body
response function formalism.