Systematizing Approximate Density Functional Design*

A meta-GGA with well-rounded accuracy and efficient numerical performance for all many-electron systems has proved to be elusive. TPSS, while accurate for many systems, never reaches predictive accuracy. SCAN [1], motivated by a need to systematize development of approximate density functionals, is often predictive, but falters for metallic systems [2]. In this talk, I’ll discuss the need to further systematize the construction of approximate density functionals. The design of possible successors to SCAN, with results for transition metals and weakly-bonded systems, as well as improvements in meta-GGA numeric efficiency from new iso-orbital indicators [3] will also be discussed.

[1] J. Sun, A. Ruzsinszky, and J. P. Perdew, Phys. Rev. Lett. 115, 036402 (2015).
[2] M. Ekholm et al., Phys. Rev. B 98, 094413 (2018).
[3] J. W. Furness and J. Sun, Phys. Rev. B 99, 041119(R) (2019).