Electronic Structure and Dynamical Correlations in Antiferromagnetic BiFeO$_3$
Fuente:
arXiv
Salvato in:
| Autori principali: | , , , |
|---|---|
| Natura: | Preprint |
| Pubblicazione: |
2025
|
| Soggetti: | |
| Accesso online: | |
| Tags: |
Aggiungi Tag
Nessun Tag, puoi essere il primo ad aggiungerne!!
|
| _version_ | 1866917111633281024 |
|---|---|
| author | Wu, Yihan Caserta, Mario Chiarotti, Tommaso Marzari, Nicola |
| author_facet | Wu, Yihan Caserta, Mario Chiarotti, Tommaso Marzari, Nicola |
| contents | We study the electronic structure and dynamical correlations in antiferromagnetic BiFeO$_3$, a prototypical room-temperature multiferroic, using a variety of static and dynamical first-principles methods. Conventional static Hubbard corrections (DFT+$U$, DFT+$U$+$V$) incorrectly predict a deep-valence Fe $3d$ peak (around $-7\,\text{eV}$) in antiferromagnetic BiFeO$_3$, in contradiction with hard-X-ray photoemission. We resolve this failure by using a recent generalization of DFT+$U$ to include a frequency-dependent screening -- DFT+$U(ω)$ -- or using a dynamical Hubbard functional (dynH). The screened Coulomb interaction $U(ω)$, computed with spin-polarized RPA and projected onto maximally localized Fe $3d$ Wannier orbitals, is expressed as a sum-over-poles, yielding a self-energy that augments the Kohn--Sham Hamiltonian. This DFT+$U(ω)$ approach predicts a fundamental band gap of $1.53\,\text{eV}$, consistent with experiments, and completely eliminates the unphysical deep-valence peak. The resulting simulated HAXPES spectrum reproduces the experimental lineshape with an accuracy matching or exceeding that of far more demanding DFT+DMFT calculations. Our work demonstrates the critical nature of dynamical screening in complex oxides and establishes DFT+$U(ω)$ as a predictive, computationally efficient method for correlated materials. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2511_23181 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Electronic Structure and Dynamical Correlations in Antiferromagnetic BiFeO$_3$ Wu, Yihan Caserta, Mario Chiarotti, Tommaso Marzari, Nicola Strongly Correlated Electrons We study the electronic structure and dynamical correlations in antiferromagnetic BiFeO$_3$, a prototypical room-temperature multiferroic, using a variety of static and dynamical first-principles methods. Conventional static Hubbard corrections (DFT+$U$, DFT+$U$+$V$) incorrectly predict a deep-valence Fe $3d$ peak (around $-7\,\text{eV}$) in antiferromagnetic BiFeO$_3$, in contradiction with hard-X-ray photoemission. We resolve this failure by using a recent generalization of DFT+$U$ to include a frequency-dependent screening -- DFT+$U(ω)$ -- or using a dynamical Hubbard functional (dynH). The screened Coulomb interaction $U(ω)$, computed with spin-polarized RPA and projected onto maximally localized Fe $3d$ Wannier orbitals, is expressed as a sum-over-poles, yielding a self-energy that augments the Kohn--Sham Hamiltonian. This DFT+$U(ω)$ approach predicts a fundamental band gap of $1.53\,\text{eV}$, consistent with experiments, and completely eliminates the unphysical deep-valence peak. The resulting simulated HAXPES spectrum reproduces the experimental lineshape with an accuracy matching or exceeding that of far more demanding DFT+DMFT calculations. Our work demonstrates the critical nature of dynamical screening in complex oxides and establishes DFT+$U(ω)$ as a predictive, computationally efficient method for correlated materials. |
| title | Electronic Structure and Dynamical Correlations in Antiferromagnetic BiFeO$_3$ |
| topic | Strongly Correlated Electrons |
| url | https://arxiv.org/abs/2511.23181 |