A projection-free method for representing plane-wave DFT results in an atom-centered basis

Area of Science:

• Computational materials science
• Quantum chemistry

Background:

• Plane wave density functional theory (DFT) provides atomic-level insights into material structures.
• Delocalized plane wave basis sets limit post-computation analysis requiring localized, atom-centered basis sets.
• Current methods bridge this gap using projection techniques.

Purpose of the Study:

• To develop a projection-free approach for calculating DFT Hamiltonian matrix elements in an atom-centered basis.
• To overcome limitations of plane wave basis sets in advanced material analysis.
• To enable wider application of post-computation analysis techniques.

Main Methods:

• Direct calculation of converged plane wave DFT Hamiltonian matrix elements in an atom-centered basis.
• Avoidance of projection-based techniques from plane wave to atom-centered basis.
• Generation of an atomic orbital representation of the Kohn-Sham wavefunction and Hamiltonian.

Main Results:

• Achieved strict orthonormality of resulting bands without artificial band mixing.
• Gained direct access to Hamiltonian matrix elements.
• Faithfully preserved the underlying DFT band structure.
• Demonstrated utility across diverse chemical systems and analysis approaches.

Conclusions:

• The projection-free method offers advantages over traditional projection techniques.
• Provides a gateway to a wider range of analysis approaches for DFT calculations.
• Facilitates more accurate and versatile analysis of material properties.