Assessing r²SCAN meta-GGA functional for structural parameters, cohesive energy, mechanical modulus, and thermophysical properties of 3d, 4d, and 5d transition metals.

This article evaluates the performance of four semilocal density functionals—local density approximation (LDA), Perdew–Burke–Ernzerhof (PBE), PBE revised for solids (PBEsol), and the revised regularized strongly constrained and appropriately normed (r²SCAN) meta-generalized gradient approximation (meta-GGA)—in predicting structural, mechanical, cohesive, and thermophysical properties of 22 transition metals across the 3d, 4d, and 5d series using the quasi-harmonic approximation (QHA). The study finds that r²SCAN offers the most balanced and accurate overall performance for equilibrium cell volumes, cohesive energies, and bulk moduli, outperforming LDA, PBE, and PBEsol in these respects. While PBEsol provides the best agreement with experimental data for thermal expansion coefficients and PBE performs best for Debye temperatures, r²SCAN's combination of accuracy and numerical efficiency makes it a recommended workhorse functional for high-throughput computational studies of refractory transition metals, their intermetallic compounds, and related alloys. The article also notes limitations such as the instability of hexagonal cobalt predicted by r²SCAN and highlights the importance of magnetic ordering in 3d metals for accurate calculations.