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Dielectric Response of Periodic Systems from Quantum Monte Carlo Calculations

P. Umari·A. J. Williamson·Giulia Galli·Nicola Marzari
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Abstract

We present a novel approach that allows to calculate the dielectric response of periodic systems in the quantum Monte Carlo formalism. We employ a many-body generalization for the electric enthalpy functional, where the coupling with the field is expressed via the Berry-phase formulation for the macroscopic polarization. A self-consistent local Hamiltonian then determines the ground-state wavefunction, allowing for accurate diffusion quantum Monte Carlo calculations where the polarization's fixed point is estimated from the average on an iterative sequence, sampled via forward-walking. This approach has been validated for the case of an isolated hydrogen atom, and then applied to a periodic system, to calculate the dielectric susceptibility of molecular-hydrogen chains. The results found are in excellent agreement with the best estimates obtained from the extrapolation of quantum-chemistry calculations.

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P. Umari, A. J. Williamson, Giulia Galli, Nicola Marzari. 2005-10-22. Dielectric Response of Periodic Systems from Quantum Monte Carlo Calculations. https://doi.org/10.1103/physrevlett.95.207602

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