Implementation of the meta-GGA exchange-correlation functional in numerical atomic orbital basis: With systematic...

Area of Science:

• Computational Physics
• Quantum Chemistry
• Materials Science

Background:

• Kohn-Sham density functional theory (DFT) is crucial for electronic structure simulations.
• Approximations to the exchange-correlation functional determine DFT accuracy and efficiency.
• Meta-generalized gradient approximation (meta-GGA) functionals, incorporating kinetic energy density, offer enhanced accuracy and flexibility.

Purpose of the Study:

• To implement meta-generalized-gradient approximation (meta-GGA) functionals within the ABACUS computational package.
• To extend the ABACUS package to support numerical atomic orbitals and plane wave bases for meta-GGA calculations.
• To validate the implementation by evaluating forces and stresses and conducting rigorous testing.

Main Methods:

• Implementation of meta-GGA functionals, including SCAN, rSCAN, and r2SCAN, in the ABACUS package.
• Utilized both numerical atomic orbitals and plane wave basis sets.
• Performed finite-difference and convergence tests for validation.
• Applied the functionals to systems including water hexamers, S22 dataset molecules, and 13 semiconductors.

Main Results:

• Successful implementation and validation of meta-GGA functionals in ABACUS.
• Demonstrated accurate evaluation of exchange-correlation potentials, forces, and stresses.
• Achieved satisfactory agreement with existing computational results and experimental data for tested systems.

Conclusions:

• The implemented meta-GGA functionals in ABACUS provide a reliable and accurate tool for electronic structure calculations.
• The enhanced capabilities of ABACUS support a wider range of quantum chemistry and materials science applications.
• This work contributes to advancing the accuracy and efficiency of DFT simulations for complex systems.