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Mailing
address:
Vanderbilt
University
Dept. of Physics & Astronomy
Box
1807-B
Nashville, TN 37235
Ph.
(615) 343-4321
Fax (615) 343-7697
E-mail:
pantelides@vanderbilt.edu
Sokrates
T. Pantelides
Distinguished
Professor of Physics and Engineering
William A. and
Nancy F. McMinn Professor of Physics
Professor
of Electrical Engineering
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Research
Associates :
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Graduate
Students:
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Tim Pennycook
Keith
Warnick
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Prof.
Pantelides Assistant: Vicki
Abernathy (615)
343-7389
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About
the research
Professor
Pantelides joined the faculty at Vanderbilt as the first William A.
and Nancy F. McMinn Professor of Physics in August 1994. His research
activities in the past spanned the following areas:
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Electronic structure and properties of bulk crystals, crystalline
surfaces, and point defects in crystals
In
this area, the main emphasis was on point defects. Theoretical
techniques were pioneered to describe quantitatively from first
principles the electronic structure of point defects in
semiconductors at the same level of sophistication that was then
possible for bulk crystals and crystalline surfaces. Other areas of
investigation were point defects and electron states at the Si-SiO2
interface, Auger life times of carriers in Si, excitonic effects in
the optical spectra of metals, x-ray absorption and excitons in ionic
insulators.
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Equilibrium atomic arrangements and atomic dynamics in crystalline
semiconductors
First-principles
computer calculations were pioneered for formation and migration
energies of point defects in semiconductors that enabled quantitative
studies of atomic diffusion and defect reactions. A number of
technologically important problems were elucidated, such as the
mechanisms of etching of Si by F ions, the mechanisms of
self-diffusion and dopant diffusion in Si, the energetics, diffusion
and complex formation of H in Si, the solubilities and doping
limitations of impurities in II-VI compound semiconductors, etc.
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The structure, point defects and dynamics of amorphous silicon
This
work was based on the recognition that there are in principle two
intrinsic point defects in amorphous silicon, namely
three*fold-coordinated and fivefold-coordinated Si atoms. The
properties of the latter were studied for the first time and later
confirmed by more sophisticated calculations. The consequences of the
dynamics of these defects and hydrogen led to systematic explanations
of many puzzling experimental observations in amorphous silicon.
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Mesoscopic dynamics in polycrystalline solids
Starting
with the fundamental axioms of quantum mechanics and statistical
mechanics a set of field equations were derived that describe
quantitatively the dynamics of heterogeneous materials at
intermediate or mesoscopic length scales. The laws of continuum
mechanics are recovered from first principles. The equations contain
elastoplasticity from first principles and allow systematic studies
of the evolution of the microstructure. Initial implementations of
the theory focused on void morphologies in polycrystalline aluminum
under electromigration conditions and the calculation of creep rates
in bicrystals.
Planned
or already started research activities at Vanderbilt will relate to
the above areas and expand in related areas. One of the problems
currently being studied are the clustering of dopant impurities in Si
and the mechanisms for dopant deactivation in heavily doped Si.
Emphasis will be placed on the problem of infrared absorption by
crystals and crystalline surfaces containing defects and other
structures. The purpose will be to explore the possibility of using
infrared radiation to steer reactions by exciting specific
vibrational modes. This work will be in conjunction with experimental
work by other faculty using the Vanderbilt Free Electron Laser
Center.
Vanderbilt
University
