Order-N implementation of exact exchange in extended systems

TL;DR

This paper presents a linear-scaling method for exact exchange calculations in extended systems using Wannier functions, enabling more efficient and accurate density functional theory computations.

Contribution

It introduces a novel linear-scaling approach combining Wannier functions and real space Coulomb integrals for exact exchange in extended systems.

Findings

Achieves linear scaling with system size

Validates the method with representative applications

Overcomes previous computational limitations

Abstract

Exact (Hartree Fock) exchange is needed to overcome some of the limitations of local and semilocal approximations of density functional theory (DFT). So far, however, computational cost has limited the use of exact exchange in plane wave calculations for extended systems. We show that this difficulty can be overcome by performing a unitary transformation from Bloch to Maximally Localized Wannier functions in combination with an efficient technique to compute real space Coulomb integrals. The resulting scheme scales linearly with system size. We validate the scheme with representative applications.