Regensburg 2019 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 92: Electronic Structure Theory

O 92.1: Vortrag

Freitag, 5. April 2019, 10:30–10:45, H5

Defining the Correlated Subspace in Hubbard-Corrected DFT using Boys Projector Functions — •Hanna Türk, Matthias Kick, Georg Michelitsch, Karsten Reuter, and Harald Oberhofer — Technical University of Munich

Hubbard-corrected density-functional theory (DFT+U) is an effective self-interaction correction method for DFT, which gained its current popularity particularly due to its high computational efficiency compared to other correction schemes. Applications of DFT+U rest, on the one hand, on a meaningful choice of the effective correction parameter U, a topic widely discussed in literature. On the other hand, though, the performance of the DFT+U scheme also critically depends on the choice of the projector operator, which determines the states the correction is applied to. Unfortunately, this aspect has received much less attention so far, even though a wrong choice of projector can lead to highly unphysical results.

In this contribution, we present a new projector for DFT+U implemented in the electronic structure code FHI-aims. It is based on Boys localized states, which are able to represent delocalized electrons of hybridized molecules better than other projectors based e.g. on localized atomic basis functions. We test the performance of the new Boys projector on an iron porphyrin molecule and compare it to atomically localized projector functions. Thereby, we demonstrate the effects of the choice of projector functions on the accuracy of DFT+U results and discuss the system specific suitability of different projectors.