Dielectric Response of Periodic Systems from Quantum Monte Carlo

ORAL

Abstract

We introduce a novel approach to study the response of periodic systems to finite homogeneous electric fields using the diffusion Quantum Monte Carlo method. The interaction with the electric field is expressed through a generalized many-body electric-enthalpy functional; a Hermitian local potential is then constructed that determines the evolution towards the ground state. This local potential depends self-consistently on the Berry-phase polarization, and is evolved ``on-the-fly'' in the course of the simulation, with the polarization operator evaluated using forward-walking. To validate this approach we calculated the dielectric susceptibility of simple molecular chains, greatly over-estimated by standard density-functional approaches, and found good agreement with the results obtained with correlated quantum-chemistry calculations.

*This work was performed under the auspices of the U.S. Department of Energy by the University of California, Lawrence Livermore National Laboratory under contract No. W-7405-Eng-48.

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Authors

  • Paolo Umari

    • DMSE-MIT

  • Andrew J. Willamson

  • Giulia Galli

    • University of California, Lawrence Livermore National Lab
    • Lawrence Livermore National Laboratory
    • Lawrence Livermore National Lab
    • Lawrence Livermore National Lab.

  • Nicola Marzari

    • Department of Materials Science and Engineering, MIT
    • DMSE, MIT, Cambridge, MA 02139
    • Department of Materials Science and Engineering, Massachusetts Institute of Technology
    • DMSE-MIT
    • Department of Materials Science and Engineering and Institute for Soldier Nanotechnologies, Massachusetts Institute of Technology
    • DMSE and ISN Massachusetts Institute of Technology
    • Materials Science and Engineering, MIT
    • Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139