On-site approximation for spin-orbit coupling in LCAO density functional methods

TL;DR

This paper introduces a simplified on-site approximation method for incorporating spin-orbit coupling into density functional theory calculations using localized atomic orbitals, achieving accurate results efficiently.

Contribution

It presents a novel on-site approximation technique for spin-orbit interactions in DFT that is easy to implement and accurate across various materials.

Findings

Accurate band structures for semiconductors and metals.

Effective approximation reduces computational complexity.

Implemented successfully in the SIESTA code.

Abstract

We propose a computational method that simplifies drastically the inclusion of spin-orbit interaction in density functional theory implemented on localised atomic orbital basis sets. Our method is based on a well-known procedure for obtaining pseudopotentials from atomic relativistic 'ab initio' calculations and on an on-site approximation for the spin-orbit matrix elements. We have implemented the technique in the SIESTA code, and we show that it provides accurate results for the overall band structure and splittings of group IV and III-IV semiconductors as well as for 5d metals.