Fermi-Löwdin orbital self-interaction correction to magnetic exchange couplings

Area of Science:

• Computational chemistry
• Condensed matter physics
• Quantum mechanics

Background:

• Self-interaction error (SIE) is a known issue in density functional theory (DFT) approximations.
• Accurate calculation of magnetic exchange couplings is crucial for understanding and designing magnetic materials.
• Existing DFT methods often struggle to precisely capture magnetic interactions due to SIE.

Purpose of the Study:

• To investigate the impact of removing self-interaction error on magnetic exchange couplings.
• To evaluate the performance of the Fermi-Löwdin orbital self-interaction correction (FLOSIC) method.
• To compare FLOSIC-corrected results with standard DFT and wave function-based methods.

Main Methods:

• Application of the Fermi-Löwdin orbital self-interaction correction (FLOSIC) within DFT.
• Calculations performed using the local spin density approximation (LSDA) framework.
• Testing on model systems: linear H-He-H, organic radicals, and [Cu2Cl6]2- complex.

Main Results:

• FLOSIC correction significantly improves magnetic exchange couplings compared to standard LSDA.
• The self-interaction-free LSDA approach yields results comparable to modern hybrid and range-separated functionals.
• Improvements were observed across various types of magnetic interactions, despite variations in exchange interaction nature.

Conclusions:

• Removing self-interaction error is essential for accurate magnetic coupling predictions in DFT.
• FLOSIC offers a computationally efficient way to improve LSDA-based magnetic coupling calculations.
• FLOSIC-corrected LSDA shows promise as a reliable method for studying magnetic phenomena.