Study of Self-Interaction Errors in Density Functional Calculations of Magnetic Exchange Coupling Constants Using...

Area of Science:

• Computational chemistry
• Quantum chemistry
• Materials science

Background:

• Self-interaction error (SIE) is a known issue in density functional approximations (DFAs).
• Accurate calculation of magnetic exchange coupling constants is crucial for understanding magnetic materials.

Purpose of the Study:

• To investigate the impact of self-interaction correction (SIC) removal on magnetic exchange coupling constants.
• To compare different one-electron SIC methods when applied to nonempirical DFAs.

Main Methods:

• Employed three one-electron SIC methods: Perdew-Zunger SIC (PZSIC), orbitalwise scaled SIC, and local scaling SIC (LSIC).
• Utilized three nonempirical DFAs: local spin density approximation, Perdew-Burke-Ernzerhof, and SCAN meta-GGA functionals.
• Computed magnetic exchange coupling constants using spin projection and nonprojection approaches for various model systems.

Main Results:

• PZSIC performs well for single-electron systems but shows overcorrection for complex organic molecules and chlorocuprates.
• LSIC with kinetic energy density ratio outperforms PZSIC for these complex systems.
• Both density and energy corrections are necessary for improved magnetic coupling predictions.

Conclusions:

• The choice of SIC method is critical for accurate magnetic exchange coupling calculations, especially for complex systems.
• LSIC offers a better alternative to PZSIC for systems where PZSIC exhibits overcorrection.
• A combined density and energy correction approach is essential for enhancing prediction accuracy.