Orbital-free density functional theory implementation with the projector augmented-wave method.

Area of Science:

• Computational materials science
• Quantum chemistry
• Condensed matter physics

Background:

• Orbital-free density functional theory (OFDFT) offers computational efficiency but often struggles with accuracy compared to all-electron methods.
• Existing OFDFT implementations face challenges with convergence and reproducing accurate all-electron properties.
• Accurate assessment of OFDFT functionals necessitates methods that can compute all-electron values.

Purpose of the Study:

• To present a novel computational scheme for OFDFT that achieves both all-electron accuracy and linear scaling.
• To address and overcome convergence issues present in other OFDFT implementations.
• To demonstrate the necessity of all-electron calculations for reliable OFDFT functional evaluation.

Main Methods:

• Utilized the projector augmented-wave (PAW) method in conjunction with real-space techniques.
• Implemented a computational scheme that preserves the linear scaling of OFDFT.
• Employed PAW to reproduce all-electron values, allowing for tunable numerical accuracy.

Main Results:

• The developed OFDFT scheme accurately reproduces all-electron values with a mean absolute error of 10 meV.
• The number of self-consistent iterations required is comparable to standard Kohn-Sham (KS) methods.
• Calculations using this method, particularly for diamond, yield lattice constants and bulk moduli comparable to the KS PBE method.

Conclusions:

• The combination of PAW and real-space methods provides a robust and accurate OFDFT implementation.
• This approach overcomes convergence issues and enables reliable assessment of OFDFT functionals.
• The developed scheme is a promising route for efficient and accurate electronic structure calculations.