Obtaining Wannier Functions of a Crystalline Insulator within a Hartree-Fock approach: Applications to LiF and LiCl

TL;DR

This paper presents a method to directly obtain Wannier functions within a Hartree-Fock framework for insulators, demonstrated on LiF and LiCl, with results matching traditional approaches and detailed orbital localization analysis.

Contribution

It introduces a direct ab initio Hartree-Fock method for localized Wannier functions in crystalline insulators, avoiding pseudo potentials and enabling detailed orbital localization studies.

Findings

Total energies agree with conventional methods

Structural factors and profiles match experimental data

Orbital localization characteristics are thoroughly analyzed

Abstract

An ab initio Hartree-Fock approach aimed at directly obtaining the localized orthogonal orbitals (Wannier functions) of a crystalline insulator is described in detail. The method is used to perform all-electron calculations on the ground states of crystalline lithium fluoride and lithium chloride, without the use of any pseudo or model potentials. Quantities such as total energy, x-ray structure factors and Compton profiles obtained using the localized Hartree-Fock orbitals are shown to be in excellent agreement with the corresponding quantities calculated using the conventional Bloch-orbital based Hartree-Fock approach. Localization characteristics of these orbitals are also discussed in detail.