@article{10902/38003,
year = {2025},
month = {6},
url = {https://hdl.handle.net/10902/38003},
abstract = {The ground state of many insulating, open-shell transition-metal perovskites with a 180° metal-ligand-metal bridge is antiferromagnetic (AFM), as predicted by Anderson's superexchange interaction or Hubbard's model. These well-established, standard models show how these systems are insulators due to the minimization of the interactions between electrons, at the cost of localizing the electrons on the metal ions. In this work, we carry out first-principles simulations on the cubic perovskites KNiF3 and KVF3, analyzing electron densities, energies and bond indices. Although our calculations predict an antiferromagnetic ordering (AFM), in agreement with canonical superexchange models, we show through various indicators that the stabilization of this phase is not mainly associated with the antibonding magnetic orbitals but rather with bonding orbitals not included in the models. In particular, these traditional descriptions of superexchange do not adequately describe the ligand-to-metal electronic backdonation, which is an important element for stabilizing the insulating state of the two studied perovskite fluorides, albeit by diametrically different mechanisms: (1) reducing electron-electron repulsion in KNiF3, as proposed by Hubbard, whereas (2) enhancing electron-nuclear attraction in KVF3. Our findings highlight some of the limitations of these foundational models and offer a novel perspective on the understanding of magnetism.},
organization = {We acknowledge financial support from Grant No. PID2022- 139776NB-C63 and PID2021-122763NB-I00 funded by MICIU/AEI/10.13039/501100011033 and by ERDF/EU. I. S.-M. acknowledges technical support and fruitful discussions with Dr. David Schnieders and Dr. Peter Müller during her stay in Aachen. I. S.-M. (Grant BDNS:589170) acknowledges financial support from Universidad de Cantabria and Gobierno de Cantabria and T.F.-R. (Grant PRE2019-089054) acknowledges financial support from Ministerio de Ciencia, Innovación y Universidades.},
publisher = {American Chemical Society},
publisher = {Inorganic Chemistry, 2025, 64(26), 13217-13223},
title = {Magnetic superexchange and mott insulator mechanisms in cubic perovskites: from first-principles to canonical models},
author = {Sánchez de Movellán Sáiz, Inés and Fernández Ruiz, Toraya and Dronskowski, Richard and Martín-Pendás, Ángel and García Fernández, Pablo (físico) and Moreno Mas, Miguel and Aramburu-Zabala Higuera, José Antonio},
}