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     COLLOQUIUM OF THE COMPUTATIONAL MATERIALS SCIENCE CENTER
AND THE SCHOOL OF PHYSICS, ASTRONOMY, & COMPUTATIONAL SCIENCES
                            (CSI 898-Sec 001)
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Computational Modeling of Bulk Photovoltaics and Dirac Semimetals
                           Steve Young
Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania
                               
In this talk I will discuss two examples from my own work where
first-principles materials modeling has yielded insights into physical
and material behavior unavailable through experiment or simple
physical models.

The first is the bulk photovoltaic effect (BPVE):  Bulk
non-centrosymmetric crystals – especially polar materials – are
capable of producing electric current in response to uniform
illumination. By direct modeling of real materials, we have shown that
“shift-current,” a proposed nonlinear optical effect, is responsible
for the experimentally observed BPVE.  Insights from these
calculations have allowed us to design and propose several
high-performing bulk photovoltaics.

The second example concerns hypothetical Dirac semimetals, which
feature symmetry-protected three-dimensional Dirac points analogous to
those found in the two-dimensional graphene.  I will discuss our
efforts to identify the fundamental, structural, and chemical features
of such a materials, and will describe a class of compounds that we
propose as candidates for realizable Dirac semimetals.

                        November 4, 2013
                              4:30 pm
             Exploratory Hall, room 3301, Fairfax Campus

Refreshments will be served at 4:15 PM.
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Find the schedule at http://www.cmasc.gmu.edu/seminars.htm