Maximilian E. Merkel¹, Claude Ederer^1*

1 Materials Theory, ETH Zürich, 8093 Zürich, Switzerland

* Corresponding authors emails: claude.ederer@mat.ethz.ch

DOI10.24435/materialscloud:1c-m7 [version v1]

Publication date: Jan 24, 2024

How to cite this record

Maximilian E. Merkel, Claude Ederer, Calculation of screened Coulomb interaction parameters for the charge-disproportionated insulator CaFeO₃, Materials Cloud Archive 2024.13 (2024), https://doi.org/10.24435/materialscloud:1c-m7

Description

We calculate the screened electron-electron interaction for the charge-disproportionated insulator CaFeO₃ using the constrained random-phase approximation (cRPA). While in many correlated materials, the formation of a Mott-insulating state is driven by a large local Coulomb repulsion, represented by the Hubbard U, several cases have been identified more recently where U is strongly screened and instead the Hund's interaction J dominates the physics. Our results confirm a strong screening of the local Coulomb repulsion U in CaFeO₃ whereas J is much less screened and can thus stabilize a charge-disproportionated insulating state. This is consistent with the case of the rare-earth nickelates where similar behavior has been demonstrated. In addition, we validate some common assumptions used for parametrizing the local electron-electron interaction in first-principles calculations based on density-functional theory (DFT), assess the dependence of the interaction on the choice of correlated orbitals, and discuss the use of the calculated interaction parameters in DFT+U calculations of CaFeO₃. Our work also highlights certain limitations for the direct use of cRPA results in DFT-based first-principles calculations, in particular for systems with strong entanglement between the correlated and uncorrelated bands.

Materials Cloud sections using this data

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File name	Size	Description
README.md MD5md5:0d981af2adf365a6723d706a0bd36c38	2.6 KiB	Description of the contents of data.tar.gz and short instructions on DFT and cRPA workflow
data.tar.gz MD5md5:fb2d16811aa8384cc902e642863127e4	427.4 MiB	tar.gz archive with all data and scripts for Fig. 2-3 and Table I-IV

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Keywords

perovskite charge disproportionation constrained random-phase approximation metal-insulator transition