Explicit demonstration of the equivalence between DFT+U and the Hartree-Fock limit of DFT+DMFT

Fuente: arXiv
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Autores principales: Carta, Alberto, Timrov, Iurii, Mlkvik, Peter, Hampel, Alexander, Ederer, Claude
Formato: Preprint
Publicado: 2024
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author Carta, Alberto
Timrov, Iurii
Mlkvik, Peter
Hampel, Alexander
Ederer, Claude
author_facet Carta, Alberto
Timrov, Iurii
Mlkvik, Peter
Hampel, Alexander
Ederer, Claude
contents Several methods have been developed to improve the predictions of density functional theory (DFT) in the case of strongly correlated electron systems. Out of these approaches, DFT+$U$, which corresponds to a static treatment of the local interaction, and DFT combined with dynamical mean field theory (DFT+DMFT), which considers local fluctuations, have both proven incredibly valuable in tackling the description of materials with strong local electron-electron interactions. While it is in principle known that the Hartree-Fock (HF) limit of the DFT+DMFT approach should recover DFT+$U$, demonstrating this equivalence in practice is challenging, due to the very different ways in which the two approaches are generally implemented. In this work, we introduce a way to perform DFT+$U$ calculations in Quantum ESPRESSO using Wannier functions as calculated by Wannier90, which allows us to use the same Hubbard projector functions both in DFT+$U$ and in DFT+DMFT. We benchmark these DFT+$U$ calculations against DFT+DMFT calculations where the DMFT impurity problem is solved within the HF approximation. Considering a number of prototypical materials including NiO, MnO, LaMnO$_3$, and LuNiO$_3$, we establish the sameness of the two approaches. Finally, we showcase the versatility of our approach by going beyond the commonly used atomic orbital-like projectors by performing DFT+$U$ calculations for VO$_2$ using a special set of bond-centered Wannier functions.
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id arxiv_https___arxiv_org_abs_2411_03937
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Explicit demonstration of the equivalence between DFT+U and the Hartree-Fock limit of DFT+DMFT
Carta, Alberto
Timrov, Iurii
Mlkvik, Peter
Hampel, Alexander
Ederer, Claude
Strongly Correlated Electrons
Materials Science
Several methods have been developed to improve the predictions of density functional theory (DFT) in the case of strongly correlated electron systems. Out of these approaches, DFT+$U$, which corresponds to a static treatment of the local interaction, and DFT combined with dynamical mean field theory (DFT+DMFT), which considers local fluctuations, have both proven incredibly valuable in tackling the description of materials with strong local electron-electron interactions. While it is in principle known that the Hartree-Fock (HF) limit of the DFT+DMFT approach should recover DFT+$U$, demonstrating this equivalence in practice is challenging, due to the very different ways in which the two approaches are generally implemented. In this work, we introduce a way to perform DFT+$U$ calculations in Quantum ESPRESSO using Wannier functions as calculated by Wannier90, which allows us to use the same Hubbard projector functions both in DFT+$U$ and in DFT+DMFT. We benchmark these DFT+$U$ calculations against DFT+DMFT calculations where the DMFT impurity problem is solved within the HF approximation. Considering a number of prototypical materials including NiO, MnO, LaMnO$_3$, and LuNiO$_3$, we establish the sameness of the two approaches. Finally, we showcase the versatility of our approach by going beyond the commonly used atomic orbital-like projectors by performing DFT+$U$ calculations for VO$_2$ using a special set of bond-centered Wannier functions.
title Explicit demonstration of the equivalence between DFT+U and the Hartree-Fock limit of DFT+DMFT
topic Strongly Correlated Electrons
Materials Science
url https://arxiv.org/abs/2411.03937