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           COLLOQUIUM OF THE COMPUTATIONAL MATERIALS SCIENCE CENTER
                              College of Science
                       (CDS Department CSI 898-Sec 001)
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Progress in Modeling Highly Resolved Spectroscopies in Complex Materials

                               Arun Bansil
Department of Physics,Northeastern University, Boston, Massachusetts 

Spectroscopies resolved highly in momentum, energy or spatial dimensions 
are playing a key role in unraveling the nature of the ground state and 
excitation properties of the cuprates and other complex materials. 
However, spectroscopies do not provide a direct map of the electronic 
spectrum, but act as a very complex "filter" or "mapping" of the energy 
levels, Fermi surfaces (FSs) and excitation spectra of interest. We may 
refer to the connection between the electronic spectrum and the measured 
spectra as the "matrix element effect." The nature of this matrix element 
differs greatly between different spectroscopies, and for any given 
spectroscopy, the matrix element is in general an extremely complex 
function of the phase space of the experiment. A good understanding of 
the matrix element thus becomes important not only for fully exploiting 
various spectroscopies, but also to ascertain optimal regions of the 
experimental phase space for zooming in on states of particular interest. 
With this motivation, we have been pursuing techniques for formulating 
and implementing methodologies for making direct connection between the 
electronic spectra and various highly resolved spectroscopies. In this 
talk I will highlight some of our recent work aimed at understanding 
angle-resolved photoemission (ARPES), scanning tunneling 
microscopy/spectroscopy (STM/STS) and inelastic x-ray scattering (IXS) 
work in cuprates, manganites and nano-dot systems, and the insights so 
obtained into the workings of the strange world of novel materials.


                        Monday, September 22, 2008
                                  4:30 pm
                     Room 301, Research I, Fairfax Campus

Refreshments will be served at 4:15 PM.
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Find the schedule at www.cmasc.gmu.edu/seminar/schedule.html
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