Cooperation of itinerant and localized physics in the magnetic phase diagram of 214 Ruddlesden-Popper iridates
Abstract
The 5d5 Ruddlesden-Popper iridates Sr2IrO4 and Ba2IrO4 have attracted considerable attention as spin-orbit entangled analogues of the cuprates, yet the origin of their antiferromagnetic insulating state, of Slater or of Mott-Heisenberg type, remains debated. We find that both materials sit in an intermediate regime in which itinerant and localized electrons cooperate in stabilizing the antiferromagnetic order, with Ba2IrO4 slightly more correlated than Sr2IrO4. We obtain this by computing, within dynamical mean-field theory, the interaction-temperature phase diagram of a realistic three-orbital t2g Hubbard model with spin-orbit coupling. Our study shows that neither the behavior of the gap across the Néel temperature nor the spin-polaron features of the spectral function unambiguously identify the cooperative regime, whereas the two-peak structure of the optical conductivity is reproduced only there and therefore constitutes a reliable fingerprint. By placing both compounds in a common phase diagram, our results reconcile seemingly contradictory experimental and theoretical reports, and provide a unified framework for future studies of the 214 iridates and of other spin-orbit coupled correlated materials.
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BibTeX
@misc{cassol2026cooperation,
title = {{Cooperation of itinerant and localized physics in the magnetic phase diagram of 214 Ruddlesden-Popper iridates}},
author = {Francesco Cassol and Michele Casula and Benjamin Lenz},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.33196},
eprint = {2610.33196},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.33196},
}
RIS
TY - UNPB
TI - Cooperation of itinerant and localized physics in the magnetic phase diagram of 214 Ruddlesden-Popper iridates
AU - Francesco Cassol
AU - Michele Casula
AU - Benjamin Lenz
PY - 2026
DA - 2026/10/23
PB - arXiv
DO - 10.48550/arxiv.2610.33196
UR - https://arxiv.org/abs/2610.33196
AB - The 5d^5 Ruddlesden-Popper iridates Sr_2IrO_4 and Ba_2IrO_4 have attracted considerable attention as spin-orbit entangled analogues of the cuprates, yet the origin of their antiferromagnetic insulating state, of Slater or of Mott-Heisenberg type, remains debated. We find that both materials sit in an intermediate regime in which itinerant and localized electrons cooperate in stabilizing the antiferromagnetic order, with Ba_2IrO_4 slightly more correlated than Sr_2IrO_4. We obtain this by computing, within dynamical mean-field theory, the interaction-temperature phase diagram of a realistic three-orbital t_2g Hubbard model with spin-orbit coupling. Our study shows that neither the behavior of the gap across the Néel temperature nor the spin-polaron features of the spectral function unambiguously identify the cooperative regime, whereas the two-peak structure of the optical conductivity is reproduced only there and therefore constitutes a reliable fingerprint. By placing both compounds in a common phase diagram, our results reconcile seemingly contradictory experimental and theoretical reports, and provide a unified framework for future studies of the 214 iridates and of other spin-orbit coupled correlated materials.
ER -