Core reconstruction in pseudopotential calculations

TL;DR

This paper introduces a novel embedding-based method to accurately reconstruct all-electron properties from pseudopotential calculations without simplifying assumptions, demonstrated on bulk aluminium.

Contribution

It presents a new embedding approach that reconstructs core regions in pseudopotential calculations without common approximations, enhancing accuracy of all-electron results.

Findings

Successful reconstruction of charge density for aluminium

Accurate density of states obtained

Error analysis of Green function construction

Abstract

A new method is presented for obtaining all-electron results from a pseudopotential calculation. This is achieved by carrying out a localised calculation in the region of an atomic nucleus using the embedding potential method of Inglesfield [J.Phys. C {\bf 14}, 3795 (1981)]. In this method the core region is \emph{reconstructed}, and none of the simplifying approximations (such as spherical symmetry of the charge density/potential or frozen core electrons) that previous solutions to this problem have required are made. The embedding method requires an accurate real space Green function, and an analysis of the errors introduced in constructing this from a set of numerical eigenstates is given. Results are presented for an all-electron reconstruction of bulk aluminium, for both the charge density and the density of states.