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Download Optical Properties of Finite Systems: From Small Clusters to Million-Atom Nanostructures
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Physics 599 -- Condensed Matter Physics seminars Monday, November 27, 1:30PM; Room 107 South College Optical Properties of Finite Systems: From Small Clusters to Million-Atom Nanostructures Dr. M. Claudia Troparevsky Department of Physics and Astronomy, The University of Tennessee, Knoxville, TN 37996-1200 Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6030 Semiconductor clusters have received considerable attention during the last decade due to their unusual electronic and optical properties. These properties can be radically altered, while maintaining the chemical composition of the material, by simply changing the size of the cluster. The ability to use “size” as a variable in tailoring the desired properties of the system, have made semiconductor clusters promising materials for the development of new electronic and optical devices such as light emitting diodes and solar cells. In this talk we will present calculations of the optical properties of different systems ranging from small molecules to ~106 atom quantum dots. We will discuss ab initio TDLDA methods, semiempirical methods, and the conventional configuration interaction (CI) approach. We will then present a novel CI method which can be employed to calculate multi-excitonic effects on quantum dots containing up to 104 atoms. A related area that we will sketch is the size dependence of the magnetic properties of transition metal clusters. Preliminary results will be presented for the case of icosahedral Co13 which illustrate the impact of strong onsite Coulomb correlations. The interplay between our results and Stern-Gerlach measurements of the magnetic moment should shed light on the role of the Hubbard U in these prototypes of correlated-electron behavior. Coming attractions: http://www.phys.utk.edu/courses/Fall%202006/physics599.htm December 4 Professor Pengcheng Dai, UTK/ORNL: TBA. Adolfo G. Eguiluz UTK/ORNL [email protected]
