Ab-initio calculations of absorption spectra of Si nanostructures using iterative techniques to solve the Bethe-Salpeter Equation

ORAL

Abstract

A first principle approach to solve the Bethe Salpeter equation has been recently proposed [1], that does not require the calculation of excited single particle orbitals, and thus opens the way to calculations of absorption spectra of relatively large systems. We show that the efficiency of this approach can be further improved: (i) by exploiting localization properties of the eigenvectors of the dielectric matrix entering the expression of the screened Coulomb interaction; and (ii) by adopting appropriate truncation schemes that allows one to accurately describe the dielectric matrix [2] with a small number of eigenvectors and eigenvalues . Applications to the calculation of absorption spectra of semiconducting clusters and Si nanorods will be presented. [1]D.Rocca, D.Lu and G.galli (submitted) [2]H.Wilson, F.Gygi and G.Galli, Phys. Rev. B 78, 113303 (2008); and H. Wilson, D. Lu, F. Gygi and G. Galli, Phys. Rev. B, 79, 245106, 2009.

*Work supported by grants NSF/CHE-0802907 and DOE/BES DE-FG02-06ER46262

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Authors

  • Yuan Ping

    • Department of Chemistry, University of California, Davis

  • Dario Rocca

    • Department of Chemistry, University of California, Davis

  • Deyu Lu

    • Department of Chemistry, University of California, Davis

  • Giulia Galli

    • Dept. of Chemistry and Dept. of Physics, UC Davis
    • Department of Chemistry and Department of Physics, University of California Davis
    • Dept of Chemistry \& Dept Physics, UC Davis
    • Department of Chemistry and Department of Physics, UC Davis, USA
    • Department of Chemistry and Department of Physics, University of California, Davis
    • UC Davis
    • Department of Chemistry, University of California, Davis, USA
    • University of California, Davis
    • Department of Chemistry and Department of Physics, University of California, Davis, CA, 95616
    • Department of Chemistry and Department of Physics, University of California, Davis, CA 95616
    • Chemistry Department and Physics Department UC Davis, Davis CA