More realistic band gaps from meta-generalized gradient approximations: Only in a generalized Kohn-Sham scheme

By Zeng-Hui Yang, Haowei Peng, Jianwei Sun, J. Perdew. 2016

135 citations recorded by the source corpus.

Unlike the local density approximation (LDA) and the generalized gradient approximation (GGA), calculations with meta-generalized gradient approximations (meta-GGA) are usually done according to the generalized Kohn-Sham (gKS) formalism. The exchange-correlation potential of the gKS equation is non-multiplicative, which prevents systematic comparison of meta-GGA bandstructures to those of the LDA and the GGA. We implement the optimized effective potential (OEP) of the meta-GGA for periodic systems, which allows us to carry out meta-GGA calculations in the same KS manner as for the LDA and the GGA. We apply the OEP to several meta-GGAs, including the new SCAN functional [Phys. Rev. Lett. 115, 036402 (2015)]. We find that the KS gaps and KS band structures of meta-GGAs are close to those of GGAs. They are smaller than the more realistic gKS gaps of meta-GGAs, but probably close to the less-realistic gaps in the band structure of the exact KS potential, as can be seen by comparing with the gaps of the EXX+RPA OEP potential. The well-known grid sensitivity of meta-GGAs is much more severe in OEP calculations.

Subfields: Atomic and Molecular Physics, and Optics, Condensed Matter Physics

View Paper: https://www.semanticscholar.org/paper/cc332406c0f32e5f60533b13c33983f902717bcb

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In Atomic and Molecular Physics, and Optics

Citations in the corpus

Accurate and numerically efficient r$^2$SCAN meta-generalized gradient approximation (2020, background): “This poor numerical performance in many codes mandates the use of dense integration grids which reduces SCAN’s computational eﬃciency [19, 20], and divergence in the associated XC potential has hindered the generation of SCAN pseudo-potentials [21, 22].”