Testing the r2SCAN Density Functional for the Thermodynamic Stability of Solids with and without a van der Waals Correction br

A central aim of materials discovery is an accurate and numerically reliable description of thermodynamic properties, such as the enthalpies of formation and decomposition. The r(2)SCAN revision of the strongly constrained and appropriately normed (SCAN) meta-generalized gradient approximation (meta-GGA) balances numerical stability with high general accuracy. To assess the r(2)SCAN description of solid-state thermodynamics, we evaluate the formation and decomposition enthalpies, equilibrium volumes, and fundamental band gaps of more than 1000 solids using r(2)SCAN, SCAN, and PBE, as well as two dispersion-corrected variants, SCAN+rVV10 and r(2)SCAN+rVV10. We show that r(2)SCAN achieves accuracy comparable to SCAN and often improves upon SCAN's already excellent accuracy. Although SCAN+rVV10 is often observed to worsen the formation enthalpies of SCAN and makes no substantial correction to SCAN's cell volume predictions, r2SCAN+rVV10 predicts marginally less accurate formation enthalpies than r(2)SCAN, and slightly more accurate cell volumes than r(2)SCAN. The average absolute errors in predicted formation enthalpies are found to decrease by a factor of 1.5 to 2.5 from the GGA level to the meta-GGA level. Smaller decreases in error are observed for decomposition enthalpies. For formation enthalpies r(2)SCAN improves over SCAN for intermetallic systems. For a few classes of systems-transition metals, intermetallics, weakly bound solids, and enthalpies of decomposition into compounds-GGAs are comparable to meta-GGAs. In total, r(2)SCAN and r(2)SCAN+rVV10 can be recommended as stable, general-purpose meta-GGAs for materials discovery.

Automated summary

A central aim of materials discovery is to accurately describe thermodynamic properties. This study evaluates the accuracy of the r(2)SCAN method in describing solid-state thermodynamics and compares it with other methods. The results show that r(2)SCAN achieves comparable accuracy to SCAN and often improves upon it. The average absolute errors in predicted formation enthalpies decrease by a factor of 1.5 to 2.5 from the GGA level to the meta-GGA level.