Optimizing the orbital occupation in the multiple minima problem of magnetic materials from the metaheuristic firefly...

Area of Science:

• Computational Materials Science
• Quantum Chemistry
• Solid State Physics

Background:

• Strongly correlated materials exhibit complex electronic structures with multiple energy minima.
• Identifying the true ground state is crucial for predicting material properties.
• Traditional methods struggle with the vast number of possible orbital occupations.

Purpose of the Study:

• To implement and validate the firefly algorithm for scanning orbital occupation minima in DFT+U.
• To efficiently identify the ground state occupations in strongly correlated systems.
• To provide a generalizable method for various computational codes.

Main Methods:

• Application of the firefly algorithm to optimize orbital occupations.
• Utilizing density functional theory (DFT) with Hubbard U correction.
• Testing the implementation on KCoF3 and UO2 crystals using the Abinit code.

Main Results:

• Successfully scanned multiple metastable minima of orbital occupations.
• Identified the ground state occupations in d and f electron systems.
• Demonstrated the method's validity and performance against previous approaches.

Conclusions:

• The firefly algorithm provides an efficient and generalizable solution for finding ground states in DFT+U.
• This method enhances the study of strongly correlated materials.
• Applicable to any computational code employing constrained occupation matrices.