Calculation of screened Coulomb interaction parameters for the charge-disproportionated insulator CaFeO$_3$
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arXiv
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| Format: | Preprint |
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2023
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| author | Merkel, Maximilian E. Ederer, Claude |
| author_facet | Merkel, Maximilian E. Ederer, Claude |
| contents | 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. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2310_16541 |
| institution | arXiv |
| publishDate | 2023 |
| record_format | arxiv |
| spellingShingle | Calculation of screened Coulomb interaction parameters for the charge-disproportionated insulator CaFeO$_3$ Merkel, Maximilian E. Ederer, Claude Strongly Correlated Electrons Computational Physics 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. |
| title | Calculation of screened Coulomb interaction parameters for the charge-disproportionated insulator CaFeO$_3$ |
| topic | Strongly Correlated Electrons Computational Physics |
| url | https://arxiv.org/abs/2310.16541 |