Calculation of screened Coulomb interaction parameters for the charge-disproportionated insulator CaFeO${}_3$

Abstract

We calculate the screened electron-electron interaction for the charge-disproportionated insulator CaFeO${}_3$ 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 CaFeO${}_3$ 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 CaFeO${}_3$. 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.

The supporting data for this article are openly available from the Materials Cloud Archive, https://doi.org/10.24435/materialscloud:1c-m7

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Cited by in corpus (5)

• Orbital-resolved DFT+U for molecules and solids
• Exploring the role of nonlocal Coulomb interactions in perovskite transition metal oxides
• Comparative analysis of methods for calculating Hubbard parameters using cRPA
• Constrained Random Phase Approximation: the spectral method
• Bridging constrained random-phase approximation and linear response theory for computing Hubbard parameters