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.

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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