Automated effective band structures for defective and mismatched supercells

Area of Science:

• Computational Materials Science
• Solid-State Physics
• Quantum Chemistry

Background:

• Plane-wave density functional theory (DFT) codes often use supercells for defects and incommensurate structures.
• Interpreting electronic band structures (E vs. k) is most effective in the primitive cell, aligning with ideal structures and spectroscopy.

Purpose of the Study:

• To implement a method for deriving effective band structures (EBS) from supercell calculations.
• To facilitate the analysis of defects and complex structures within the primitive cell framework.

Main Methods:

• Implementation of the Popescu and Zunger method within the CASTEP code, named bs_sc2pc.
• Utilizing supercell and primitive cell structural data with automatic symmetry handling.
• Demonstration through three test cases involving vacancies, substitutions, and lattice mismatch.

Main Results:

• Successful generation of effective band structures (EBS) from supercell calculations.
• Demonstrated efficacy in capturing the influence of structural variations on primitive cell band structures.
• Validation of the bs_sc2pc tool for analyzing defects and complex materials.

Conclusions:

• The bs_sc2pc implementation effectively bridges the gap between supercell calculations and primitive cell band structure interpretation.
• This method simplifies the analysis of defects and structural complexities in materials science.
• The tool aids in comparing computational results with experimental spectroscopy.