Altermagnetism in MnF2: Band Splitting and Its Physical Consequences
Abstract
MnF2 is widely regarded as a candidate altermagnet, but the magnitude and implications of its altermagnetic band splitting remain debated. Using electronic-structure calculations, we construct minimal models that capture the magnetic and electronic properties of MnF2. These models show that the parameters governing the chiral magnon splitting and the spin splitting of the electronic bands are relatively small. Moreover, the electronic system lies in the strong-coupling regime, where most magnetic properties are controlled by the ratio t/U between the characteristic hopping amplitude t and the large on-site Coulomb repulsion U. Consequently, all exchange interactions scale as 1/U, so a small altermagnetic hopping δt produces only a proportionally small exchange term. Upon doping, the altermagnetic contribution to the anomalous Hall effect is likewise suppressed, being smaller than the conventional (non-altermagnetic) contribution by a factor of order δt/U. In contrast, the behavior of the conductivity tensor σ̂(ω) at ℏ ω∼ U differs qualitatively, because δt enters the energies of interband optical transitions \emph{directly} rather than through the reduced ratio δt/U. This contribution strongly reshapes σ̂(ω), leading to a dramatic enhancement of the magneto-optical response.
Related
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BibTeX
@misc{solovyev2026altermagnetism,
title = {{Altermagnetism in MnF$_2$: Band Splitting and Its Physical Consequences}},
author = {Igor Solovyev},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2606.01515},
eprint = {2606.01515},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2606.01515},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Altermagnetism in MnF_2: Band Splitting and Its Physical Consequences
AU - Igor Solovyev
PY - 2026
DA - 2026/10/06
PB - arXiv
DO - 10.48550/arxiv.2606.01515
UR - https://arxiv.org/abs/2606.01515
AB - MnF_2 is widely regarded as a candidate altermagnet, but the magnitude and implications of its altermagnetic band splitting remain debated. Using electronic-structure calculations, we construct minimal models that capture the magnetic and electronic properties of MnF_2. These models show that the parameters governing the chiral magnon splitting and the spin splitting of the electronic bands are relatively small. Moreover, the electronic system lies in the strong-coupling regime, where most magnetic properties are controlled by the ratio t/U between the characteristic hopping amplitude t and the large on-site Coulomb repulsion U. Consequently, all exchange interactions scale as 1/U, so a small altermagnetic hopping δt produces only a proportionally small exchange term. Upon doping, the altermagnetic contribution to the anomalous Hall effect is likewise suppressed, being smaller than the conventional (non-altermagnetic) contribution by a factor of order δt/U. In contrast, the behavior of the conductivity tensor σ̂(ω) at ℏ ω∼ U differs qualitatively, because δt enters the energies of interband optical transitions \emph{directly} rather than through the reduced ratio δt/U. This contribution strongly reshapes σ̂(ω), leading to a dramatic enhancement of the magneto-optical response.
ER -