Construction and solution of a Wannier-functions based Hamiltonian in the pseudopotential plane-wave framework for strongly correlated materials

TL;DR

This paper presents a comprehensive ab initio scheme combining Wannier functions, DFT, DMFT, and QMC within a pseudopotential plane-wave framework to accurately model strongly correlated materials, exemplified by nickel oxide.

Contribution

It introduces a novel self-contained method to construct and solve Hamiltonians for correlated materials using Wannier functions and ab initio parameters within a plane-wave approach.

Findings

Good agreement with experimental photoemission spectra for nickel oxide.

Effective calculation of Coulomb interaction parameter U for Wannier functions.

Applicable to structural relaxations influenced by correlation effects.

Abstract

Ab initio determination of model Hamiltonian parameters for strongly correlated materials is a key issue in applying many-particle theoretical tools to real narrow-band materials. We propose a self-contained calculation scheme to construct, with an ab initio approach, and solve such a Hamiltonian. The scheme uses a Wannier-function-basis set, with the Coulomb interaction parameter U obtained specifically for these Wannier functions via constrained Density functional theory (DFT) calculations. The Hamiltonian is solved by Dynamical Mean-Field Theory (DMFT) with the effective impurity problem treated by the Quantum Monte Carlo (QMC) method. Our scheme is based on the pseudopotential plane-wave method, which makes it suitable for developments addressing the challenging problem of crystal structural relaxations and transformations due to correlation effects. We have applied our scheme to the "charge transfer insulator" material nickel oxide and demonstrate a good agreement with the experimental photoemission spectra.