Spectral Representation analysis of dielectric screening in solids and molecules

ORAL

Abstract

We propose a new approach to identify and rationalize the contribution of core electron polarization to dielectric screening, based on ab initio calculations of the dielectric matrix in its eigenpotential basis. We also present calculations of phonon frequencies, dielectric constants for alkali hydrides and quasiparticle energies of several sp bonded molecules, and we discuss the quantitative effect of including core polarization. We find that inclusion of semi-core (SC) electrons leads to new eigenmodes in the dielectric matrix with respect to those with valence electron only. These eigenmodes are highly localized in real space. Polarization arising from SC orbitals may contribute 4-6\% to the computed dielectric constants in alkali hydrides, and to differences in QP energies of $\sim$100 meV for sp bonded molecules. Our findings illustrate efficient ways of approximating the spectral decomposition of dielectric matrices used, e.g. in many body perturbation theory and dielectric constant calculations, with substantial computational gains for large systems composed of heavy atoms.

*Work supported by DOE/SciDac-e grant DE-FC02-06ER25777, DOE/SciDac grant DE-FC02-06ER25794. This work was also supported by Guru Gobind Singh Fellowship.

–

Authors

  • Amandeep Kaur

    • University of California, Davis, CA

  • Erik Ylvisaker

    • University of California, Davis, CA

  • Deyu Lu

    • Center for Functional Nanomaterials, Brookhaven National Laboratory, NY
    • Center for Functional Nanomaterials, Brookhaven National Laboratory

  • Tuan Anh Pham

    • Department of Chemistry, University of California Davis
    • Lawrence Livermore National Laboratory and Department of Chemistry UC Davis
    • Department of Chemistry UC Davis and Lawrence Livermore National Laboratory
    • Department of Chemistry, University of California, Davis
    • University of California, Davis, CA

  • Giulia Galli

    • Department of Chemistry, University of California Davis
    • Department of Chemistry, Department of Physics, University of California, Davis
    • University of California - Davis
    • Department of Chemistry and Department of Physics UC Davis
    • University of California, Davis
    • Department of Chemistry and Department of Physics, University of California, Davis
    • UC Davis
    • Department of Chemistry and Department of Physics, UC Davis
    • University of California, Davis, CA

  • Warren Pickett

    • University of California, Davis, CA