Finite-size correction in many-body electronic structure calculations of magnetic systems

TL;DR

This paper extends a finite-size correction method for many-body electronic structure calculations to spin-polarized systems, enabling more accurate and efficient simulations of magnetic materials without costly large-scale computations.

Contribution

It develops a unified finite-size correction functional for spin polarized systems within DFT, improving convergence in magnetic system simulations.

Findings

Significantly reduces finite-size errors in magnetic systems

Achieves rapid convergence to infinite system results

Applicable to various supercell sizes and spin polarizations

Abstract

We extend the post-processing finite-size (FS) correction method, developed by Kwee, Zhang, and Krakauer [Phys. Rev. Lett. 100, 126404 (2008)], to spin polarized systems. The method estimates the FS effects in many-body electronic structure calculations of extended systems by a modified density functional theory (DFT) calculation, without having to repeat expensive many-body simulations. We construct a unified FS DFT exchange-correlation functional for spin unpolarized and fully spin polarized systems, under the local density approximation. The results are then interpolated to arbitrary spin polarizations. Generalization to other functional forms in DFT are discussed. The application of this FS correction method to several typical magnetic systems with varying supercell sizes demonstrates that it consistently removes most of the FS errors, leading to rapid convergence of the many-body results to the infinite size limit.