Analysis of over-magnetization of elemental transition metal solids from the SCAN Density Functional

Abstract

Recent investigations have found that the strongly constrained and appropriately normed (SCAN) meta-GGA exchange-correlation functional significantly over-magnetizes elemental Fe, Co, and Ni solids. For the paradigmatic case, bcc Fe, the error relative to experiment is $\gtrsim 20\%$. Comparative analysis of magnetization results from SCAN and its \textit{deorbitalized} counterpart, SCAN-L, leads to identification of the source of the discrepancy. It is not from the difference between Kohn-Sham (SCAN-L) and generalized Kohn-Sham (SCAN) procedures. The key is the iso-orbital indicator $\alpha$ (the ratio of the local Pauli and Thomas-Fermi kinetic energy densities). Its \textit{deorbitalized} counterpart, ${\alpha }_L$, has more dispersion in both spin channels with respect to magnetization in an approximate region between 0.6 Bohr and 1.2 Bohr around an Fe nucleus. The overall effect is that the SCAN switching function evaluated with ${\alpha }_L$ reduces the energetic disadvantage of the down channel with respect to up compared to the original $\alpha$, which in turn reduces the magnetization. This identifies the cause of the SCAN magnetization error as insensitivity of the SCAN switching function to $\alpha$ values in the approximate range $0.5\lesssim \alpha \lesssim 0.8$ and oversensitivity for $\alpha \gtrsim 0.8$.

arXiv comment5 pages, 5 figures, revised version

References in corpus (13)

• Climbing the Density Functional Ladder: Non-Empirical Meta-Generalized Gradient Approximation Designed for Molecules and Solids
• Regularized SCAN functional
• More-Realistic Band Gaps from Meta-Generalized Gradient Approximations: Only in a Generalized Kohn-Sham Scheme
• Performance of the strongly constrained and appropriately normed density functional for solid-state materials
• Applicability of the strongly constrained and appropriately normed density functional to transition metal magnetism
• Accurate semilocal density functional for condensed matter physics and quantum chemistry
• Deorbitalized meta-GGA Exchange-Correlation Functionals in Solids
• Deorbitalization strategies for meta-GGA exchange-correlation functionals
• Assessing the SCAN functional for itinerant electron ferromagnets
• Density Functional Methods for the Magnetism of Transition Metals: SCAN in Relation to Other Functionals
• Performance of Tao-Mo semilocal density functional in projector-augmented-wave method
• Enhancing the efficiency of density functionals with a novel iso-orbital indicator
• Orbital-free approximations to the kinetic-energy density in exchange-correlation MGGA functionals: tests on solids

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