Dear pymatgen/Materials Project community,
I’ve been exploring the new r2SCAN metaGGA functional approach used in the Materials Project database and have some specific questions regarding the GGA_GGA+U_R2SCAN mixing adjustment.
From the Materials Project website, I understand that “formation energies have now been calculated with the r2SCAN metaGGA functional, which improves the accuracy of reported thermodynamic data.” When examining the data for material mp-3527 (Na₃AgO₂), I noticed:
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The GGA_GGA+U_R2SCAN mixed approach shows an energy adjustment described as “MP GGA(+U)/r2SCAN mixing adjustment: 53.6587 eV (4.4716 eV/atom)”
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This appears to shift the r2SCAN calculated energy (-8.524 eV/atom) to match the corrected GGA/GGA+U scale (-4.052 eV/atom)
I’d appreciate clarification on:
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What is the exact workflow for implementing this mixing scheme? Do you first perform separate GGA/GGA+U and r2SCAN calculations and then apply a post-processing correction?
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Is there a standardized approach for calculating the mixing adjustment for different materials, or is it system-dependent?
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Is there documentation or code examples available for how to reproduce this mixing approach for my own calculations?
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How was this mixing scheme validated, and what improvements in accuracy does it provide over pure GGA/GGA+U or pure r2SCAN calculations?
Thank you for your time. Any insights or pointers to relevant documentation or code would be extremely helpful for my research.
Sincerely,
Zhao