Space partitioning of exchange-correlation functionals with the projector augmented-wave method

TL;DR

This paper presents a method for space partitioning of exchange-correlation functionals within the GPAW density functional theory code, enabling different regions of a system to be treated with tailored functionals, demonstrated on metallic alloys.

Contribution

The authors implement a Becke fuzzy cells space partitioning scheme for exchange-correlation functionals in GPAW, facilitating region-specific functional treatment in DFT calculations.

Findings

Successful implementation of the space partitioning scheme

Validation through test calculations confirms correctness

Application to metallic alloys demonstrates practical utility

Abstract

We implement a Becke fuzzy cells type space partitioning scheme for the purposes of exchange-correlation within the GPAW projector augmented-wave method based density functional theory code. Space partitioning is needed in the situation where one needs to treat different parts of a combined system with different exchange-correlation functionals. For example, bulk and surface regions of a system could be treated with functionals that are specifically designed to capture the distinct physics of those regions. Here we use the space partitioning scheme to implement the quasi-nonuniform exchange-correlation scheme, which is a useful practical approach for calculating metallic alloys on the generalized gradient approximation level. We also confirm the correctness of our implementation with a set of test calculations.