---------- Forwarded message ----------
From: Stopa, Michael <stopa(a)lsdiv.harvard.edu>
Date: Mon, Dec 3, 2012 at 10:36 AM
Subject: talk today
To: Aspuru-Assistant <aspuru.assistant(a)gmail.com>
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Hi Cynthia,****
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Alan sent this announcement around last week for me. It is about a talk
today at noon by my visitor.****
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Could you send this as a reminder to the group this morning? Thanks!****
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-Mike****
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This Monday (today!!), Dr. Normand Modine from Sandia National Labs will be
visiting. He is giving a talk which includes lunch and is summarized below.*
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Computing Semiconductor Defect Properties: Band Gap Levels and Beyond****
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Dr. Normand A. Modine****
Sandia National Laboratories****
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Date: Monday, December 3, 2012****
Time: 12:00 noon****
Where: LISE 303****
What else: lunch provided for those who RSVP****
RSVP: send a note indicating plan to attend to stopa(a)cns.fas.harvard.edu****
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abstract****
Calculations based on the Kohn-Sham Density Functional Theory (DFT) have
been widely used to predict the band-gap levels of point defects in
semiconductors. Several additional defect properties are needed in order to
fully understand how defects influence the behavior of materials. We will
discuss a set of ongoing efforts to predict defect properties using a
general approach in which DFT at the atomistic scale is coupled with other
models in order to bridge to longer length and time scales. For example,
DFT results interpreted in light of a set of approximate bounds on the
defect levels are combined with Franck-Condon theory in order to obtain
activation energies for carrier-capture at defects. Likewise, kinetic
Monte-Carlo simulations based on energies obtained from a cluster expansion
fit to DFT results help us predict the effects of alloying on defect
diffusion. Finally, rate equations and kinetic Monte-Carlo incorporating
parameters obtained from DFT are used to investigate the effects of
non-equilibrium carrier concentrations on defect diffusion and defect
induced carrier recombination. The results of these calculations help us
understand technologically important phenomena in solid-state lighting and
the annealing of radiation damage.****
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