Binghamton University
Department of Physics, Applied Physics and Astronomy
Department of Materials Science and Engineering
PHYSICS COLLOQUIUM
Bruce White
Associate Professor and Director of Undergraduate Studies,
Department of Physics Applied Physics and Astronomy,
Binghamton University
“Lattice Vibrations in Amorphous Thin Films – A Path to
Nanocomposite based Energy Conversion?”
Abstract:
It has been over thirty five years since the first unequivocal demonstration of the anomalous low
temperature lattice vibrations in amorphous solids. While theses lattice vibrations have been successfully
explained by the presence of a broad distribution of tunneling entities in these materials, the identification of
these tunneling entities has not been accomplished for even a single amorphous solid. Moreover, an explanation
for the near universal spectral density of tunneling states has remained a mystery. In this presentation we will
discuss how these lattice vibrations manifest themselves in thin amorphous films. In particular we will describe
a technique for measuring the elastic properties of amorphous thin films as a probe of these lattice vibrations.
We will demonstrate that the universal anomalous lattice vibrations remain in tact in these films down to
thicknesses corresponding to two monolayers. With these results in mind, we will ask the question of whether the
surfaces of reduced dimensionality structures can be manipulated to produce a thermal conductivity that is below
that expected from diffuse scattering of lattice vibrations at surfaces. If so, this could provide a path to
artificially created solids with the optimum electronic and thermal properties required for efficient solid state
energy conversion.
Monday, December 3rd, 2007
S2 Bldg. Room 243
PRESENTATION 2:30 PM– 3:30PM
ALL WELCOME – COFFEE AND REFRESHMENTS AT 2:20PM