A DFT+U type functional derived to explicitly address the flat plane condition

TL;DR

This paper introduces a new first-principles derived DFT+U functional that explicitly enforces the flat plane condition, significantly improving energy accuracy for certain molecular systems.

Contribution

A novel DFT+U functional derived from first principles that directly enforces the flat plane condition without relying on ad hoc Hubbard model derivations.

Findings

Achieves less than 0.6% error in total energy calculations.

Outperforms traditional PBE and PBE+U functionals in accuracy.

Reduces errors in dissociated molecular systems.

Abstract

A new DFT+U type corrective functional is derived from first principles to enforce the flat plane condition on localized subspaces, thus dispensing with the need for an ad hoc derivation from the Hubbard model. The newly derived functional as given by equation 5 yields relative errors below 0.6% in the total energy of the dissociated s-block dimers as well as the dissociated H5+ ring system. In comparison bare PBE and PBE+U (using Dudarev's 1998 Hubbard functional) yields relative energetic errors as high as 8.0% and 20.5% respectively.