Pith. sign in

REVIEW 3 major objections 5 minor 14 cited by

Altermagnetism revealed by polarized neutrons in MnF$_2$

T0 review · 3 major / 5 minor · reviewed 2026-08-04 · deepseek-v4-flash

Challenge this review Re-run · record.json Download PDF Read on arXiv ↗

Pith's one-line read MnF2, long treated as the textbook antiferromagnet, is shown to be an altermagnet: the chiral term in polarized neutron scattering flips sign between its two magnon branches, and the paper ties this uniquely to a micro-eV J7a-J7b exchange i

desk verdict Real signal, credible experiment, but the leap to 'altermagnetism demonstrated' rests on a model-completeness assumption the paper itself leaves open. read the letter →

arxiv 2509.07087 v1 pith:OE5CTZBU submitted 2025-09-08 cond-mat.str-el cond-mat.mes-hallcond-mat.mtrl-sci

Quentin Faure , Dalila Bounoua , Victor Balédent , Arsen Gukasov , V. Ovidiu Garlea , Afonso Ribeiro , Jeffrey G. Rau , Sylvain Petit
show 1 more author
Paul McClarty
This is my paper
classification cond-mat.str-elcond-mat.mes-hallcond-mat.mtrl-sci
keywords altermagnetismMnF2polarizedinelasticneutronscatteringmagnonchiralityspinwavesantiferromagnetdipolarcouplingchiralcrosssection
verification ladder T0 review T1 audit T2 compute T3 formal

The pith

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The reading

This paper sets out to show that MnF2—a material that has served for decades as the canonical example of a two-sublattice antiferromagnet—is actually an altermagnet, a collinear magnet whose crystal symmetry allows spin-split excitations without a net magnetization. Using polarized inelastic neutron scattering on a crystal biased toward one antiferromagnetic domain, the authors resolve a roughly 0.2 meV splitting of the two magnon (spin-wave) branches and, more importantly, isolate a chiral term in the cross section that changes sign between the lower and upper modes. Within linear spin-wave theory, a symmetry-restricted enumeration of two-spin couplings identifies the microscopic source as the tiny inequality J7a≠J7b between two distinct seventh-neighbor Heisenberg exchange bonds—an energy scale of order 10 μeV, far below the instrumental resolution. If correct, the result reclassifies a textbook antiferromagnet as a d-wave altermagnet and shows that polarized neutrons can detect altermagnetism directly from magnetic excitations, even when the altermagnetic splitting is dwarfed by non-altermagnetic ones like the dipolar splitting.

What carries the argument

The load-bearing object is the chiral term of the polarized neutron cross section, isolated by subtracting intensities for +Pin and -Pin: I_+ - I_- ∝ (-1)^n (Pin·k)(k·N) C_k δ(ω-ε_k^n). Because this term changes sign with the magnon index n, it is the direct fingerprint of magnon chirality. The supporting machinery is a symmetry-lowered spin-wave model: the fluoride ions reduce the lattice symmetry from body-centered tetragonal to a four-fold rotation plus half-translation and time reversal, and only the two distinct seventh-neighbor Heisenberg bonds J7a and J7b carry that symmetry. An altermagnetic splitting appears when J7a≠J7b; the long-range dipolar interaction also splits the modes but,

What would settle it

Measure the chiral difference map on a crystal whose majority domain is reversed (for example, field-cooled into the opposite 4:1 imbalance): if MnF2's altermagnetism is the cause, the chiral signal flips sign with the Néel vector while the unpolarized sum stays unchanged. Alternatively, a linear spin-wave calculation adding a symmetry-allowed two-spin or 2n-spin coupling that produces a comparable sign-reversing chiral term would falsify the paper's uniqueness claim.

Watch

Extended reading notes

Core claim

The central discovery is a nonzero chiral term in MnF2's polarized neutron cross section, isolated by subtracting intensities for opposite incident polarizations. The term is proportional to (-1)^n (Pin·k)(k·N), reversing sign between the two magnon branches; it is visible only because the crystal is biased 85:15 toward one antiferromagnetic domain. Along (H,H,1) the chiral signal peaks near H=0.35 and dies at the zone boundary, matching the d-wave chirality pattern dictated by symmetry. Spin-wave fits give J7a-J7b on the micro-eV scale, and an enumeration of symmetry-allowed two-spin couplings singles out this seventh-neighbor imbalance as the only one that yields a net chiral term. The pap

Load-bearing premise

The identification of altermagnetism rests on the unproven premise that, among all couplings allowed by symmetry in MnF2, only the small J7a-J7b imbalance can create the observed sign-reversing chiral signal; the paper itself leaves 2n-spin (n≥2) couplings to future work and assumes spin-orbit and single-ion anisotropies are negligible, so an omitted coupling with the same fingerprint would weaken the conclusion.

Editorial extensions

If this is right

  • If the result holds, MnF2 becomes a confirmed altermagnet whose fingerprint is read from the magnetic excitations themselves, not from electronic bands, placing it beside MnTe and CrSb in the list of established altermagnets.
  • The measured chiral ratio (5–11% of the integrated intensity) pins J7a-J7b to the micro-eV range, showing that a symmetry-breaking energy two orders of magnitude below the magnon bandwidth can still produce a detectable polarization signal.
  • Symmetry guarantees the chiral term reverses between (H,H,1) and (H,-H,1); a future measurement at the symmetry-related wavevector that fails to show the opposite sign would refute the altermagnetic assignment.
  • The protocol—domain-biased single crystal, half-polarized neutrons, and a +Pin/−Pin difference map—provides a general way to identify altermagnets even when the altermagnetic splitting is buried under larger non-altermagnetic splittings.
  • The fitted exchange parameters, including J7a and J7b, give a benchmark for modeling d-wave altermagnetism in rutile-structure insulators with pure-spin moments.

Reading between the lines

Editorial extensions of the paper, not claims the author makes directly.

  • A clean control experiment would be to cool a fresh crystal through TN in a field that selects the minority domain: the chiral signal should reverse sign while the unpolarized spectrum remains unchanged.
  • The same half-polarized protocol could be applied to other collinear antiferromagnets in the rutile family; a small survey would show whether micro-eV seventh-neighbor exchange imbalances are generic or peculiar to MnF2.
  • If the chiral intensity is as sensitive as reported, polarized inelastic neutron scattering may become a way to constrain anisotropic and multi-spin exchange terms that are invisible in fits to the unpolarized dispersion, using chirality as a fine-structure magnifier.
Share X Bluesky LinkedIn Reddit HN

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, and a circularity audit.

Referee Report

3 major / 5 minor

Summary. The paper reports polarized inelastic neutron scattering experiments on MnF2, a collinear antiferromagnet in space group P4_2/mnm, using a crystal with an approximately 85±5% single-domain population. Unpolarized data resolve a small (~0.178 meV) splitting of the two magnon branches, attributed mainly to long-range magnetostatic dipolar coupling. Half-polarized measurements with the incident polarization aligned along Q yield a difference spectrum between +P_in and -P_in that reverses sign between the two magnon branches. The authors fit a Heisenberg exchange model through seventh-neighbor couplings plus dipolar interactions to the dispersion, obtaining J7a-J7b ≈ 0.004 meV, and argue from a symmetry enumeration of two-spin couplings that the only such coupling generating a nonzero chiral term in linear spin-wave theory is this Heisenberg imbalance. They conclude that the sign-reversing chirality 'clearly demonstrates altermagnetism in MnF2.'

Significance. If the inference holds, this is an important advance: a direct, polarized-neutron observation of magnon chirality in a compensated collinear antiferromagnet, and a demonstration that magnetic fine structure below the dipolar scale can be probed through the chiral cross section. The experiment is carefully designed: the domain population is characterized by flipping-ratio measurements, the chiral signal is a direct difference of two polarization channels, the sign reversal is not a fit parameter, and the spin-wave calculations include long-range dipolar interactions via Ewald summation and fit more than 1600 dispersion points. These are genuine strengths. However, the central claim that the chiral signal uniquely demonstrates altermagnetism is tied to a model-completeness assumption that the manuscript itself leaves open, the statistical significance of the difference signal is not quantified, and the relation to a very recent null result for altermagnetic splitting in MnF2 is not addressed. The result is plausible and potentially important, but the claims as written outrun the evidence.

major comments (3)
  1. [Supplementary Text, 'A priori constraints on the anisotropic couplings' (final paragraph and Table S3)] The uniqueness proof that the observed chiral term is the fingerprint of the J7a-J7b imbalance is explicitly conditional: it considers only two-spin couplings out to seventh neighbors, only linear spin-wave theory, and assumes single-ion/spin-orbit terms are negligible. The paragraph immediately before the conclusion defers '2n-spin (n≥2) couplings' to future studies. The inferred altermagnetic scale, |J7a-J7b| ≈ 0.004 meV, is two orders of magnitude below the 0.178 meV dipolar splitting and comparable to the single-ion anisotropy scale D_c ≈ 0.027 meV used in a recent fit (Ref. 42). A symmetry-allowed four-spin ring-exchange or biquadratic term compatible with P4_2/mnm could, in principle, produce a sign-reversing chiral signal of the observed 5-11% with J7a=J7b. To support the abstract's 'clearly demonstrates altermagnetism,' the authors should either extend the enumeration to multi-sp
  2. [Main text, 'Chirality of magnon bands' and Figs. 3(e-f), S5, S6] The central evidence for a nonzero chiral term is the difference between the +P_in and -P_in intensities, yet the difference spectra in Fig. 3(e-f) and Fig. S5 are plotted without error bars. The integrated chiral ratio is quoted as 'between 5% and 11%' and '~11±1%' (Fig. S6), but no statistical significance test is reported. The statement that the signal 'goes to zero, within errors' at H=1/2 presupposes an error estimate that is not shown. Please propagate counting statistics (including the 85±5% domain dilution) and provide confidence intervals on the fitted Gaussian areas in the difference channel, or otherwise quantify the significance of the sign-reversing difference. Without this, the reader cannot assess whether the chiral signal is statistically established.
  3. [References and Notes, Ref. [42]; Supplementary 'Parameterization of the dispersion relations'] The paper cites a very recent study, Morano et al., 'Absence of Altermagnetic Magnon Band Splitting in MnF2' (Phys. Rev. Lett. 134, 226702, 2025), but only as a comparison of exchange parameters. This prior work appears to have searched specifically for altermagnetic magnon band splitting in MnF2 and reports its absence. The present manuscript reports a well-resolved splitting and a chiral signal in the same material. The discrepancy must be addressed explicitly: is it due to different resolution, a different sample/domain state, different model assumptions (single-ion vs. dipolar anisotropy), or a different interpretation? Without this reconciliation, the experimental claim is incomplete in an important respect.
minor comments (5)
  1. [Main text, 'Chirality of magnon bands'] The references to Fig. 3 panels are inconsistent: the sum and difference maps are panels (a) and (c), not (c) and (e); 'Focussing on panel (e)' should refer to the difference map (c), while the constant-Q scans are in panels (e-f).
  2. [Main text, fit parameters] The sentence 'J7a = -0.006 meV and J7a = -0.002 meV' should read J7b for the second coupling.
  3. [Supplementary, 'Parameterization of the dispersion relations'] The text 'The figure constrains |J7a-J7b| ≈ 0.04' should be 0.004 meV, consistent with Fig. S10 axes and the main text δJ7 < 5 μeV.
  4. [Main text, microscopic origins paragraph] The phrase 'a fold-fold rotation symmetry' should read 'a four-fold rotation symmetry.'
  5. [Fig. S6 caption] The caption contains a duplicated 'of of'; please correct to 'Q dependence of the ratio.'

Circularity Check

0 steps flagged · score 0.0 of 10

No significant circularity: the chiral signal is a direct experimental observable, and the model is used only to interpret it, with an acknowledged model-completeness caveat.

full rationale

The paper's central claim rests on a directly measured polarized-neutron difference map (Fig. 3e) that shows a sign-reversing chiral term between the two magnon branches; this is not a fitted quantity. The cross-section formula used (Eq. 1) is re-derived from first principles in the Supplementary (Eqs. S13-S16), so the citation to Ref. 34 (which shares authors) is not load-bearing. The inference that J7a-J7b is the source of the chiral term is supported by an explicit enumeration of symmetry-allowed two-spin couplings in the Supplementary ('we have shown that the sole two-spin coupling that generates a non-vanishing chiral term within linear spin wave theory is the imbalance between Heisenberg J7 couplings'), not by an imported uniqueness theorem. The magnitude of |J7a-J7b| is then constrained from the measured chiral ratio (Fig. S10), which is an independent use of data, not a prediction from the fit. The main circularity risk would be if the chiral term were defined as the model's J7 imbalance; instead it is an experimental observable. The Supplementary explicitly defers 2n-spin (n>=2) couplings ('It is also conceivable that 2n-spin (n>=2) couplings play a role in the altermagnetism in MnF2 but we leave an examination of these to future studies') and assumes negligible spin-orbit terms; this is a model-completeness limitation that weakens the uniqueness argument as a matter of physics, but it is not a circular reduction of the conclusion to the inputs. No derivation step equates a prediction to a fit by construction.

Assumptions & free parameters 8 free parameters · 4 assumptions · 0 invented entities

The central claim of altermagnetism in MnF2 rests on eight fitted exchange couplings, a fixed dipolar energy, and a restricted model space. The experimental chiral asymmetry is direct, but its interpretation as altermagnetic depends on the assumption that no omitted coupling generates the same signal.

free parameters (8)
  • J1 = -0.075(2) meV
    Heisenberg exchange coupling at the first-neighbor shell, fitted to roughly 1600 dispersion points.
  • J2 = 0.287(3) meV
    Dominant antiferromagnetic exchange between the two sublattices, fitted to the dispersion.
  • J3 = -0.012(1) meV
    Fitted exchange coupling at the third-neighbor shell.
  • J4 = -0.001(1) meV
    Fitted exchange coupling, consistent with zero within errors.
  • J5 = 0.008(2) meV
    Fitted exchange coupling at the fifth-neighbor shell.
  • J6 = 0.001(2) meV
    Fitted exchange coupling, consistent with zero within errors.
  • J7a = -0.006(3) meV
    Fitted seventh-neighbor coupling; its imbalance with J7b is required to generate the altermagnetic chiral signal.
  • J7b = -0.002(3) meV
    Fitted seventh-neighbor coupling, strongly anticorrelated with J7a; |J7a-J7b| is constrained to the micro-eV scale by the chiral intensity ratio.
assumptions (4)
  • domain assumption The minimal Hamiltonian is Heisenberg exchange up to seventh neighbor plus a fixed long-range dipolar coupling (Eq. S1).
    Central model for all calculated dispersions and chiralities; it excludes further-neighbor and multi-spin couplings that could alter the chiral signal.
  • domain assumption Spin-orbit coupling and single-ion anisotropy are negligible, so moments remain collinear along c.
    Justifies pure Heisenberg exchange and attributes the magnon gap to dipolar coupling; the Supplementary admits B2^2-type terms but argues they are below threshold.
  • domain assumption Within linear spin-wave theory and this model space, the only coupling that produces a net chiral term is J7a-J7b.
    Derived in the Supplementary for two-spin couplings out to seventh neighbor, but 2n-spin couplings are explicitly left to future work, so this model-space restriction is load-bearing.
  • standard math Multiboson or flavor-wave expansion and bosonic Bogoliubov diagonalization give the magnon spectra and cross sections.
    Standard spin-wave machinery; validity for S=5/2 MnF2 is reasonable but not independently verified in this paper.

how reviews work

0 comments
Cite this review

Pith. "Pith review of Altermagnetism revealed by polarized neutrons in MnF$_2$." pith.science (2026). https://pith.science/paper/OE5CTZBU

@misc{pith2026250907087,
  author       = {Pith},
  title        = {Pith review of: Altermagnetism revealed by polarized neutrons in MnF$_2$},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/OE5CTZBU}},
  note         = {Machine review of arXiv:2509.07087}
}
abstract

Motivated by possible spintronics applications in antiferromagnets, it was recently observed that symmetry admits magnets that combine attractive features of both ferromagnets and antiferromagnets. These systems, dubbed altermagnets, have been the subject of intense study with direct spectroscopic evidence, from ARPES and RIXS, techniques reported in a handful of materials in the last year. Inelastic neutron scattering (INS) is one of the most powerful direct probes of magnetism and has recently been used to witness a splitting of magnon bands in MnTe that is compatible with altermagnetism although the nature and origin of the splitting remain to be fully characterized. However, the full power of neutron scattering for such systems comes from using polarized neutrons to measure the chirality of the magnon bands. Such a measurement provides a direct characterization of altermagnetism directly from the spin wave excitations. In this article, we present results on MnF$_2$ once thought to be an archetypal antiferromagnet. We present a polarized INS data that demonstrate the material is, in fact, altermagnetic. It had long been realized that the magnon bands in this material should have a weak splitting coming from the long-range dipolar coupling. Our data is the first to visualize this splitting directly. While the dipolar splitting on its own is not altermagnetic, using a domain biased sample, the data reveals a nonzero chirality in the neutron scattering cross section that reverses sign between the two magnon modes. It is this feature that clearly demonstrates altermagnetism in MnF$_2$. This finding highlights the potential for polarized INS to characterize altermagnets not least through its exquisite sensitivity to fine-structure in the magnon spectrum.

Discussion (0). Sign in to comment.

Forward citations

Cited by 14 Pith papers

Reviewed papers in the Pith corpus that reference this work. Sorted by Pith novelty score.

  1. $d$-wave altermagnetism revealed by resonant inelastic X-ray scattering

    cond-mat.str-el 2026-06 unverdicted novelty 7.0 of 10

    RIXS circular dichroism with d-wave symmetry in La2O3Mn2Se2 provides evidence for d-wave altermagnetism independent of magnon splitting.

  2. Chiral Magnons and Cycloidal Phonons in Altermagnetic CuF$_{2}$ Monolayer

    cond-mat.mtrl-sci 2026-06 unverdicted novelty 7.0 of 10

    Monolayer CuF2 exhibits directionally complementary chiral magnons and cycloidal phonons under P2_1/c symmetry with quantized magnon Chern numbers ±2.

  3. Synthetic Altermagnetism Beyond the Crystal Limit

    cond-mat.other 2026-06 unverdicted novelty 7.0 of 10

    Synthetic altermagnetism is realized in a continuum platform of antiferromagnetically coupled ferromagnetic films with alternating in-plane exchange anisotropies, reproducing momentum-dependent magnon splitting, nodal...

  4. Experimental investigation of altermagnetic order in Cr-doped FeSb2

    cond-mat.mtrl-sci 2026-05 unverdicted novelty 7.0 of 10

    Magnetization, transport, and muon spin relaxation measurements provide evidence for altermagnetic order in Fe0.85Cr0.15Sb2 below ~3.5 K with time-reversal symmetry breaking but no net magnetization.

  5. Resonance-enhanced super-superexchange yields giant chiral magnon splitting in rutile altermagnets

    cond-mat.mtrl-sci 2026-04 unverdicted novelty 7.0 of 10

    Rutile CuF2 exhibits meV-scale chiral magnon splitting arising from resonance-enhanced super-superexchange that amplifies the difference in seventh-neighbor exchanges.

  6. Coherent high-velocity chiral magnons in the metallic altermagnet CrSb

    cond-mat.mtrl-sci 2025-11 conditional novelty 7.0 of 10

    CrSb is a high-temperature metallic altermagnet with coherent magnons of group velocities 61 and 58 km/s that exhibit chiral momentum-space splitting, described by a minimal Heisenberg model with alternating exchange ...

  7. Stacking-dependent anisotropic altermagnetism in V$_{1/3}$NbS$_2$

    cond-mat.str-el 2026-07 conditional novelty 6.0 of 10

    In V1/3NbS2, the vanadium-layer stacking determines both the magnetic easy axis and the anomalous Hall response, with AB and ABC polytypes showing perpendicular A-type altermagnetic order.

  8. Magnetic Field Control of the N\'eel Vector and Magnon Visibility in Altermagnetic MnTe

    cond-mat.str-el 2026-07 accept novelty 6.0 of 10

    In-plane fields reorient the Néel vector in α-MnTe, leaving chiral magnon energies and linewidths unchanged while modifying spectral intensity via the transverse-momentum projector.

  9. Nonlinear Optical Probing of Ferroic-Octupolar Order Parameter in Collinear Altermagnet

    cond-mat.str-el 2026-06 unverdicted novelty 6.0 of 10

    SHG in CoF2 is shown to be sensitive to the ferroic-octupolar magnetic order parameter in the altermagnetic phase via resonant three-photon processes and symmetry-allowed quadrupolar polarization.

  10. Strong electron correlations and ligand hybridization for altermagnetism

    cond-mat.str-el 2026-05 unverdicted novelty 6.0 of 10

    Strong correlations suppress spin splitting in MnF2 via band narrowing, enable it in MnTe through Mn 3d-Te 5p hybridization, and produce itinerant splitting without local moments in RuO2.

  11. Experimental investigation of altermagnetic order in Cr-doped FeSb2

    cond-mat.mtrl-sci 2026-05 unverdicted novelty 6.0 of 10

    Cr doping of FeSb2 breaks time-reversal symmetry with bulk short-range spin-compensated order below ~3.5 K but does not stabilize long-range collinear altermagnetic order.

  12. Altermagnetic and dipolar splitting of magnons in FeF$_2$

    cond-mat.str-el 2026-01 conditional novelty 6.0 of 10

    In FeF2, dipolar interactions dominate the observed magnon splitting; a small altermagnetic splitting of about 35 μeV is inferred from line broadening at half-integer L.

  13. Magnon-polaron mediated spin Seebeck effect in altermagnets

    cond-mat.mes-hall 2026-07 unverdicted novelty 5.0 of 10

    Altermagnets under magnetic field exhibit field-dependent in-plane anisotropy in spin Seebeck coefficient plus resonant peaks from magnetoelastic coupling that serve as signatures of altermagnetic order.

  14. Chiral Magnons: Mechanisms and Research Progress

    cond-mat.str-el 2026-07 conditional novelty 2.0 of 10

    Chiral magnons with ω(k)≠ω(−k) arise from DMI, altermagnetic exchange, and spin-space-group symmetries, enabling non-reciprocal magnonic transport and devices.

Reference graph

Works this paper leans on

52 extracted references · 21 canonical work pages · cited by 13 Pith papers

  1. [1]

    ˇSmejkal, R

    L. ˇSmejkal, R. Gonz´alez-Hern´andez, T. Jungwirth, J. Sinova, Crystal time-reversal symmetry breaking and spontaneous Hall effect in collinear antiferromagnets.Science Advances6(23), eaaz8809 (2020), doi:10.1126/sciadv.aaz8809

    doi:10.1126/sciadv.aaz8809 2020

  2. [2]

    (0, 0, 1) (1 2 , 1 2 , 1) (1 2 , 1 2 , 1

    work page

  3. [3]

    (a) inelastic neutron spectra along high- symmetry directions within the Brillouin zone (inset) obtained with an incident energy of𝐸 𝑖 = 9 meV

    (1, 1, 0) (1 2 , 1 2 , 0) Z a Γ M A Z Γ MZ b c d e f Figure 2: Unpolarized inelastic neutron spectra of MnF2. (a) inelastic neutron spectra along high- symmetry directions within the Brillouin zone (inset) obtained with an incident energy of𝐸 𝑖 = 9 meV. Blue circles shows energies of the magnetic modes obtained from fits of the data using a sum of Gaussia...

    work page

  4. [4]

    Hayami, Y

    S. Hayami, Y. Yanagi, H. Kusunose, Momentum-Dependent Spin Splitting by Collinear An- tiferromagnetic Ordering.Journal of the Physical Society of Japan88(12), 123702 (2019), doi:10.7566/JPSJ.88.123702. 12

    doi:10.7566/jpsj.88.123702 2019

  5. [5]

    ˇSmejkal, J

    L. ˇSmejkal, J. Sinova, T. Jungwirth, Beyond Conventional Ferromagnetism and Antiferro- magnetism: A Phase with Nonrelativistic Spin and Crystal Rotation Symmetry.Phys. Rev. X 12, 031042 (2022), doi:10.1103/PhysRevX.12.031042,https://link.aps.org/doi/10. 1103/PhysRevX.12.031042

    doi:10.1103/physrevx.12.031042 2022

  6. [6]

    ˇSmejkal, J

    L. ˇSmejkal, J. Sinova, T. Jungwirth, Emerging Research Landscape of Altermagnetism.Phys. Rev. X12, 040501 (2022), doi:10.1103/PhysRevX.12.040501,https://link.aps.org/ doi/10.1103/PhysRevX.12.040501

    doi:10.1103/physrevx.12.040501 2022

  7. [7]

    Jungwirth,et al., Altermagnetism: An unconventional spin-ordered phase of matter

    T. Jungwirth,et al., Altermagnetism: An unconventional spin-ordered phase of matter. Newton1(6), 100162 (2025), doi:https://doi.org/10.1016/j.newton.2025.100162,https: //www.sciencedirect.com/science/article/pii/S2950636025001549

    arXiv 2025

  8. [8]

    Bhowal, N

    S. Bhowal, N. A. Spaldin, Ferroically Ordered Magnetic Octupoles in𝑑-Wave Altermagnets. Phys. Rev. X14, 011019 (2024), doi:10.1103/PhysRevX.14.011019,https://link.aps. org/doi/10.1103/PhysRevX.14.011019

    doi:10.1103/physrevx.14.011019 2024

Show all 52 references
  1. [9]

    P. A. McClarty, J. G. Rau, Landau Theory of Altermagnetism.Phys. Rev. Lett.132, 176702 (2024), doi:10.1103/PhysRevLett.132.176702,https://link.aps.org/doi/10. 1103/PhysRevLett.132.176702

    2024 doi

  2. [10]

    Lee,et al., Broken Kramers Degeneracy in Altermagnetic MnTe.Phys

    S. Lee,et al., Broken Kramers Degeneracy in Altermagnetic MnTe.Phys. Rev. Lett.132, 036702 (2024), doi:10.1103/PhysRevLett.132.036702,https://link.aps.org/doi/10. 1103/PhysRevLett.132.036702

    2024 doi

  3. [11]

    Z. Liu, M. Ozeki, S. Asai, S. Itoh, T. Masuda, Chiral Split Magnon in Altermagnetic MnTe. Phys. Rev. Lett.133, 156702 (2024), doi:10.1103/PhysRevLett.133.156702,https://link. aps.org/doi/10.1103/PhysRevLett.133.156702

    2024 doi

  4. [12]

    Krempask´ y,et al., Altermagnetic lifting of Kramers spin degeneracy.Nature626(7999), 517–522 (2024), doi:10.1038/s41586-023-06907-7

    J. Krempask´ y,et al., Altermagnetic lifting of Kramers spin degeneracy.Nature626(7999), 517–522 (2024), doi:10.1038/s41586-023-06907-7

    2024 doi

  5. [13]

    Osumi,et al., Observation of a giant band splitting in altermagnetic MnTe.Phys

    T. Osumi,et al., Observation of a giant band splitting in altermagnetic MnTe.Phys. Rev. B109, 115102 (2024), doi:10.1103/PhysRevB.109.115102,https://link.aps.org/doi/ 10.1103/PhysRevB.109.115102. 13

    2024 doi

  6. [14]

    M. Hajlaoui,et al., Temperature Dependence of Relativistic Valence Band Splitting Induced by an Altermagnetic Phase Transition.Advanced Materials36(31), 2314076 (2024), doi: 10.1002/adma.202314076

    2024 doi

  7. [15]

    Chilcote,et al., Stoichiometry-induced ferromagnetism in altermagnetic candidate MnTe

    M. Chilcote,et al., Stoichiometry-induced ferromagnetism in altermagnetic candidate MnTe. arXiv e-printsarXiv:2406.04474 (2024), doi:10.48550/arXiv.2406.04474

    2024 doi arXiv

  8. [16]

    O. J. Amin,et al., Altermagnetism imaged and controlled down to the nanoscale.arXiv e-prints arXiv:2405.02409 (2024), doi:10.48550/arXiv.2405.02409

    2024 doi arXiv

  9. [17]

    Reimers,et al., Direct observation of altermagnetic band splitting in CrSb thin films.Nature Communications15, 2116 (2024), doi:10.1038/s41467-024-46476-5

    S. Reimers,et al., Direct observation of altermagnetic band splitting in CrSb thin films.Nature Communications15, 2116 (2024), doi:10.1038/s41467-024-46476-5

    2024 doi

  10. [18]

    Ding,et al., Large Band Splitting in𝑔-Wave Altermagnet CrSb.Phys

    J. Ding,et al., Large Band Splitting in𝑔-Wave Altermagnet CrSb.Phys. Rev. Lett.133, 206401 (2024), doi:10.1103/PhysRevLett.133.206401,https://link.aps.org/doi/10. 1103/PhysRevLett.133.206401

    2024 doi

  11. [19]

    M. Zeng,et al., Observation of Spin Splitting in Room-Temperature Metallic Antifer- romagnet CrSb.Advanced Science11(43), 2406529 (2024), doi:https://doi.org/10.1002/ advs.202406529,https://advanced.onlinelibrary.wiley.com/doi/abs/10.1002/ advs.202406529

    2024

  12. [20]

    Li,et al., Topological Weyl altermagnetism in CrSb.Communications Physics8(1), 311 (2025), doi:10.1038/s42005-025-02232-9

    C. Li,et al., Topological Weyl altermagnetism in CrSb.Communications Physics8(1), 311 (2025), doi:10.1038/s42005-025-02232-9

    2025 doi

  13. [21]

    Lu,et al., Signature of Topological Surface Bands in Altermagnetic Weyl Semimetal CrSb

    W. Lu,et al., Signature of Topological Surface Bands in Altermagnetic Weyl Semimetal CrSb. Nano Letters25(18), 7343–7350 (2025), doi:10.1021/acs.nanolett.5c00482

    2025 doi

  14. [22]

    Yang,et al., Three-dimensional mapping of the altermagnetic spin splitting in CrSb.Nature Communications16(1), 1442 (2025), doi:10.1038/s41467-025-56647-7

    G. Yang,et al., Three-dimensional mapping of the altermagnetic spin splitting in CrSb.Nature Communications16(1), 1442 (2025), doi:10.1038/s41467-025-56647-7

    2025 doi

  15. [23]

    Biniskos,et al., Systematic Mapping of Altermagnetic Magnons by Resonant Inelastic X-Ray Circular Dichroism.arXiv preprint arXiv:2503.02533(2025)

    N. Biniskos,et al., Systematic Mapping of Altermagnetic Magnons by Resonant Inelastic X-Ray Circular Dichroism.arXiv preprint arXiv:2503.02533(2025). 14

    2025

  16. [24]

    Litvin, W

    D. Litvin, W. Opechowski, Spin groups.Physica76(3), 538–554 (1974), doi:https: //doi.org/10.1016/0031-8914(74)90157-8,https://www.sciencedirect.com/science/ article/pii/0031891474901578

    1974

  17. [25]

    D. B. Litvin, Spin point groups.Acta Crystallographica Section A33(2), 279–287 (1977), doi:10.1107/S0567739477000709,https://doi.org/10.1107/S0567739477000709

    1977 doi

  18. [26]

    P. Liu, J. Li, J. Han, X. Wan, Q. Liu, Spin-Group Symmetry in Magnetic Materials with Negligible Spin-Orbit Coupling.Phys. Rev. X12, 021016 (2022), doi:10.1103/PhysRevX.12. 021016,https://link.aps.org/doi/10.1103/PhysRevX.12.021016

    2022 doi

  19. [27]

    Corticelli, R

    A. Corticelli, R. Moessner, P. A. McClarty, Spin-space groups and magnon band topology. Phys. Rev. B105, 064430 (2022), doi:10.1103/PhysRevB.105.064430,https://link.aps. org/doi/10.1103/PhysRevB.105.064430

    2022 doi

  20. [28]

    Schiff, A

    H. Schiff, A. Corticelli, A. Guerreiro, J. Romh ´anyi, P. McClarty, The Spin Point Groups and their Representations.arXiv e-printsarXiv:2307.12784 (2023), doi:10.48550/arXiv.2307. 12784

    2023 doi arXiv

  21. [29]

    Z. Xiao, J. Zhao, Y. Li, R. Shindou, Z.-D. Song, Spin Space Groups: Full Classification and Applications.Phys. Rev. X14, 031037 (2024), doi:10.1103/PhysRevX.14.031037,https: //link.aps.org/doi/10.1103/PhysRevX.14.031037

    2024 doi

  22. [30]

    Chen,et al., Enumeration and Representation Theory of Spin Space Groups.Phys

    X. Chen,et al., Enumeration and Representation Theory of Spin Space Groups.Phys. Rev. X 14, 031038 (2024), doi:10.1103/PhysRevX.14.031038,https://link.aps.org/doi/10. 1103/PhysRevX.14.031038

    2024 doi

  23. [31]

    Jiang,et al., Enumeration of Spin-Space Groups: Toward a Complete Description of Sym- metries of Magnetic Orders.Phys

    Y. Jiang,et al., Enumeration of Spin-Space Groups: Toward a Complete Description of Sym- metries of Magnetic Orders.Phys. Rev. X14, 031039 (2024),https://link.aps.org/doi/ 10.1103/PhysRevX.14.031039

    2024 doi

  24. [32]

    ˇSmejkal,et al., Chiral Magnons in Altermagnetic RuO 2.Phys

    L. ˇSmejkal,et al., Chiral Magnons in Altermagnetic RuO 2.Phys. Rev. Lett.131, 256703 (2023), doi:10.1103/PhysRevLett.131.256703,https://link.aps.org/doi/10. 1103/PhysRevLett.131.256703. 15

    2023 doi

  25. [33]

    Gohlke, A

    M. Gohlke, A. Corticelli, R. Moessner, P. A. McClarty, A. Mook, Spurious Symmetry En- hancement in Linear Spin Wave Theory and Interaction-Induced Topology in Magnons.Phys. Rev. Lett.131, 186702 (2023), doi:10.1103/PhysRevLett.131.186702,https://link.aps. org/doi/10.1103/PhysR...

    2023 doi

  26. [34]

    Cichutek, P

    N. Cichutek, P. Kopietz, A. R¨ uckriegel, Spontaneous magnon decay in two-dimensional al- termagnets.Phys. Rev. Res.7, 033208 (2025), doi:10.1103/b5vs-ldpm,https://link.aps. org/doi/10.1103/b5vs-ldpm

    2025 doi

  27. [35]

    Eto,et al., Spontaneous magnon decays from nonrelativistic time-reversal symmetry break- ing in altermagnets.arXiv e-printsarXiv:2502.20146 (2025), doi:10.48550/arXiv.2502.20146

    R. Eto,et al., Spontaneous magnon decays from nonrelativistic time-reversal symmetry break- ing in altermagnets.arXiv e-printsarXiv:2502.20146 (2025), doi:10.48550/arXiv.2502.20146

    2025 doi arXiv

  28. [36]

    P. A. McClarty, A. Gukasov, J. G. Rau, Observing altermagnetism using polarized neutrons. Phys. Rev. B111, L060405 (2025), doi:10.1103/PhysRevB.111.L060405,https://link. aps.org/doi/10.1103/PhysRevB.111.L060405

    2025 doi

  29. [37]

    Okazaki, K

    A. Okazaki, K. C. Turberfield, R. W. H. Stevenson, Neutron inelastic scattering measurements of antiferromagnetic excitations in MnF2 at 4.2 K and at temperatures up to N ´eel point.Phys. Lett.8, 9 (1964), doi:10.1016/0031-9163(64)90774-7

    1964 doi

  30. [38]

    K. C. Turberfield, A. Okazaki, R. W. H. Stevenson, The development of the magnetic excitation spectra of MnF2 with increasing temperature.Proc. Phys. Soc.85(4), 743 (1965), doi:10.1088/ 0370-1328/85/4/315

    1965

  31. [39]

    Nikotin, P

    O. Nikotin, P. A. Lindg ˚ard, O. W. Dietrich, Magnon dispersion relation and exchange interac- tions in MnF2.J. Phys. Condens. Matter.2(7), 1168 (1969), doi:10.1088/0022-3719/2/7/309

    1969 doi

  32. [40]

    T. M. Holden, E. C. Svensson, W. J. L. Buyers, R. A. Cowley, R. W. H. Stevenson, Two- Magnon Scattering of Neutrons by MnF2.Journal of Applied Physics41(3), 896–897 (1970), doi:10.1063/1.1659007

    1970 doi

  33. [41]

    Schweika, S

    W. Schweika, S. V. Maleyev, T. Br¨ uckel, V. P. Plakhty, L. P. Regnault, Longitudinal spin fluctu- ations in the antiferromagnet MnF2 studied by polarized neutron scattering.EPL (Europhysics Letters)60(3), 446–452 (2002), doi:10.1209/epl/i2002-00284-x. 16

    2002 doi

  34. [42]

    Yamani, Z

    Z. Yamani, Z. Tun, D. H. Ryan, Neutron scattering study of the classical antiferromagnet MnF2: a perfect hands-on neutron scattering teaching course.Canadian Journal of Physics88(10), 771–797 (2010), doi:10.1139/P10-081

    2010 doi

  35. [43]

    K. F. Tseng, T. Keller, A. C. Walters, R. J. Birgeneau, B. Keimer, Neutron spin-echo study of the critical dynamics of spin- 5 2 antiferromagnets in two and three dimensions.Phys. Rev. B94, 014424 (2016), doi:10.1103/PhysRevB.94.014424,https://link.aps.org/doi/10. 1103/PhysRev...

    2016 doi

  36. [44]

    V. C. Morano,et al., Absence of Altermagnetic Magnon Band Splitting in MnF 2.Phys. Rev. Lett.134, 226702 (2025), doi:10.1103/PhysRevLett.134.226702,https://link.aps.org/ doi/10.1103/PhysRevLett.134.226702

    2025 doi

  37. [45]

    Nambu,et al., Observation of Magnon Polarization.Phys

    Y. Nambu,et al., Observation of Magnon Polarization.Phys. Rev. Lett.125, 027201 (2020), doi:10.1103/PhysRevLett.125.027201,https://link.aps.org/doi/10.1103/ PhysRevLett.125.027201

    2020 doi

  38. [46]

    Jenni,et al., Chirality of magnetic excitations in ferromagnetic SrRuO 3.Phys

    K. Jenni,et al., Chirality of magnetic excitations in ferromagnetic SrRuO 3.Phys. Rev. B105, L180408 (2022), doi:10.1103/PhysRevB.105.L180408,https://link.aps.org/doi/10. 1103/PhysRevB.105.L180408

    2022 doi

  39. [47]

    See Supplemental Material at URL-will-be-inserted-by-publisher

  40. [48]

    Buckingham, P

    A. Buckingham, P. Stephens, Magnetic optical activity.Annual review of physical chemistry 17(1), 399–432 (1966)

    1966

  41. [49]

    Nathans, H

    R. Nathans, H. Alperin, S. Pickart, P. Brown, Measurement of the Covalent Spin Distribution in Manganous Fluoride Using Polarized Neutrons.Journal of Applied Physics34(4), 1182–1186 (1963)

    1963

  42. [50]

    A. S. (ORNL), I. Z. (BNL), SHIVER Software (2019),https://neutrons.github.io/ Shiver/

    2019

  43. [51]

    A. K. Dagnino,et al., The landscape of symmetry enhancement in tight-binding models.arXiv e-printsarXiv:2409.02999 (2024), doi:10.48550/arXiv.2409.02999. 17

    2024 doi arXiv

  44. [52]

    decoration

    F. Allen,et al., International Tables for Crystallography, Vol. C, edited by AJC Wilson.Dor- drecht: Kluwer), Part6, 476 (1992). Acknowledgments Funding:This research used resources at the Spallation Neutron Source, a DOE Office of Science User Facility operated by the Oak Rid...

    1992

Pith tools

Reviewed August 4, 2026 · model on record in the stance chip above.