Density functional theory (DFT) in chemistry and materials science aims for “chemical accuracy,” but this goal is challenged by the need to approximate the exact exchange-correlation (XC) energy functional. The restored-regularized strongly constrained and appropriately normed (${\mathrm{r}}^2\mathrm{SCAN}$), meta-generalized gradient approximation to the XC functional fulfills 17 exact constraints of the XC energy, and has significantly boosted prediction accuracy for molecules and materials. However, ${\mathrm{r}}^2\mathrm{SCAN}$ remains inadequate at predicting the properties of open $d$ and $f$ transition-metal strongly correlated compounds, such as band gaps, magnetic moments, and oxidation energies. Prediction inaccuracies of ${\mathrm{r}}^2\mathrm{SCAN}$ energies arise from functional- and density-driven errors, mainly resulting from the DFT self-interaction error. Here, we propose a method termed ${\mathrm{r}}^2\mathrm{SCANY}$@${\mathrm{r}}^2\mathrm{SCANX}$ to mitigate the self-interaction error of XC functionals for the accurate simulations of electronic, magnetic, and thermochemical properties of transition-metal oxides. ${\mathrm{r}}^2\mathrm{SCANY}$@${\mathrm{r}}^2\mathrm{SCANX}$ uses different fractions of exact Hartree-Fock exchange, X for the electronic density and Y for the density functional approximation of the total energy, thereby simultaneously addressing functional-driven and density-driven inaccuracies. Building on just one (or maximum two) parameters that apply unchanged to s-p-bonded systems, we demonstrate that ${\mathrm{r}}^2\mathrm{SCANY}$@${\mathrm{r}}^2\mathrm{SCANX}$ improves upon the ${\mathrm{r}}^2\mathrm{SCAN}$ predictions for 20 highly correlated oxides and even outperforms the highly parametrized DFT(${\mathrm{r}}^2\mathrm{SCAN}$)$+U$ method—the state-of-the-art approach to predict strongly correlated materials. Prediction uncertainties for oxidation energies and magnetic moments of transition-metal oxides are significantly reduced by ${\mathrm{r}}^2\mathrm{SCAN}10@{\mathrm{r}}^2\mathrm{SCAN}50$ and band gaps with ${\mathrm{r}}^2\mathrm{SCAN}10@{\mathrm{r}}^2\mathrm{SCAN}$. ${\mathrm{r}}^2\mathrm{SCAN}10@{\mathrm{r}}^2\mathrm{SCAN}50$ diminishes the density-driven error of the energy in ${\mathrm{r}}^2\mathrm{SCAN}$ and ${\mathrm{r}}^2\mathrm{SCAN}10$. We demonstrate that the computationally efficient ${\mathrm{r}}^2\mathrm{SCAN}10@{\mathrm{r}}^2\mathrm{SCAN}$ is nearly as accurate as the global hybrid ${\mathrm{r}}^2\mathrm{SCAN}10$ for oxidation energies. This indicates that accurate energy differences can be obtained through rate-limiting self-consistent iterations and geometry optimizations with the efficient ${\mathrm{r}}^2\mathrm{SCAN}$. Subsequently, a more expensive nonlocal functional, such as a hybrid or self-interaction correction, can be applied in a fast, single post-self-consistent calculation, as in ${\mathrm{r}}^2\mathrm{SCAN}10$@${\mathrm{r}}^2\mathrm{SCAN}$.

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• Complex oxides
• Strongly correlated systems
• Transition metal oxides
• Density functional calculations
• Density functional theory development
• First-principles calculations
• Hybrid functionals
• Meta-GGA