pith. sign in

arxiv: 2605.01872 · v1 · submitted 2026-05-03 · ❄️ cond-mat.mtrl-sci · cond-mat.mes-hall

Reversible fully spin polarization in strain-engineered two-dimensional fully compensated magnets

Xiuli Zhang , Peng Jiang , Yurui Ma , Xiaodong Zhou , Linlin Liu , Hong-Mei Huang , San-Dong Guo , Tengfei Cao
show 1 more author
Yan-Ling Li
This is my paper

Pith reviewed 2026-05-09 16:53 UTC · model grok-4.3

classification ❄️ cond-mat.mtrl-sci cond-mat.mes-hall
keywords strain engineeringaltermagnetismfully compensated ferrimagnetspin polarizationtwo-dimensional magnetsreversible switchingspintronics
0
0 comments X

The pith

Strain turns altermagnets into fully spin-polarized compensated magnets

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

The paper shows that uniaxial strain applied to two-dimensional fully compensated magnets breaks symmetry by making magnetic sublattices inequivalent. This transition from altermagnetic to fully compensated ferrimagnetic state produces complete spin polarization in the transport. Orthogonal strain directions create two degenerate states with opposite polarization directions for reversible switching. Calculations confirm this in materials including Mn2SeO and V2SO, providing a symmetry-based way to control spin in compensated systems.

Core claim

Uniaxial strain removes the constraints on spin polarization in two-dimensional altermagnets by inducing inequivalence between magnetic sublattices. This drives the system into a fully compensated ferrimagnetic state enabling fully spin-polarized transport. Strain along orthogonal directions produces two energetically degenerate states with opposite spin polarization, allowing reversible spin switching. The mechanism is general and applies to ferroelastic fFIM systems as well, as verified by symmetry analysis, tight-binding models, first-principles calculations, and Boltzmann transport theory in Mn2SeO and V2SO.

What carries the argument

Strain-induced inequivalence between magnetic sublattices that converts altermagnetic states to fully compensated ferrimagnetic states with full spin polarization

If this is right

  • Complete spin polarization is achieved in fully compensated magnets under uniaxial strain.
  • Reversible switching of the spin polarization direction occurs by rotating the strain axis by 90 degrees.
  • The approach extends to ferroelastic fully compensated ferrimagnets for potential nonvolatile applications.
  • A universal symmetry-driven framework for strain-controlled spin transport in 2D magnets is established.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • This mechanism could be combined with other 2D material properties like piezoelectricity for integrated devices.
  • The reversible states might serve as basis for strain-tunable spin filters in nanoelectronics.
  • Real-world implementation would depend on maintaining magnetic order under applied strain without defects.

Load-bearing premise

The minimal tight-binding model and symmetry analysis are sufficient to describe the strain effects on spin polarization in these materials without higher-order corrections or external perturbations dominating.

What would settle it

If spin-resolved transport calculations or experiments on strained Mn2SeO show less than full spin polarization, the central claim would be falsified.

Figures

Figures reproduced from arXiv: 2605.01872 by Hong-Mei Huang, Linlin Liu, Peng Jiang, San-Dong Guo, Tengfei Cao, Xiaodong Zhou, Xiuli Zhang, Yan-Ling Li, Yurui Ma.

Figure 1
Figure 1. Figure 1: FIG. 1. (a) The illustration of uniaxial strain engineering view at source ↗
Figure 2
Figure 2. Figure 2: FIG. 2. (a) Atomic structure, spin density, and (b) spin-pol view at source ↗
Figure 3
Figure 3. Figure 3: FIG. 3. (a) Band structure and IDOS, (b) spin-resolved condu view at source ↗
Figure 4
Figure 4. Figure 4: FIG. 4. (a) Crystal structure and spin density, (b) spin pola view at source ↗
read the original abstract

Achieving controllable spin polarization and its reversal in symmetry-compensated magnets. Here we demonstrate, using symmetry analysis and a minimal tight-binding model, that uniaxial strain removes these constraints by inducing inequivalence between magnetic sublattices in two-dimensional (2D) system, driving an altermagnetic (AM) state into a fully compensated ferrimagnetic (fFIM) state and enabling fully spin polarization. Furthermore, strain along orthogonal directions gives rise to two energetically degenerate fFIM states with opposite spin polarization, enabling reversible spin switching. More importantly, the two symmetry-related fFIM states can be regarded as distinct ferroelastic variants, suggesting that this model or mechanism can be extended to ferroelastic fFIM systems. The generality of this mechanism is confirmed by combining spin-group analysis, first-principles calculations, and Boltzmann transport theory in representative candidates, including AM Mn$_2$SeO and ferroelastic fFIM V$_2$SO. Our results reveal a universal symmetry-driven framework for strain-controlled and -reversible fully spin-polarized transport and identify strain-engineered AM and ferroelastic fFIM systems as a promising platform for volatile and nonvolatile spintronic applications.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

3 major / 2 minor

Summary. The manuscript claims that uniaxial strain applied to two-dimensional altermagnets induces inequivalence between magnetic sublattices, driving a transition from an altermagnetic (AM) state to a fully compensated ferrimagnetic (fFIM) state that supports fully spin-polarized transport. Orthogonal strain directions produce energetically degenerate fFIM states with opposite spin polarization, enabling reversible switching. The mechanism is supported by spin-group symmetry analysis, a minimal tight-binding model, first-principles calculations on candidate materials Mn2SeO and V2SO, and Boltzmann transport theory, with the fFIM states also interpretable as ferroelastic variants.

Significance. If the central claims hold, the work establishes a symmetry-based, strain-tunable route to fully polarized spin currents in compensated magnets, which is significant for spintronic applications requiring controllable and reversible polarization without net magnetization. The integration of general symmetry principles with material-specific first-principles validation and transport calculations is a positive feature, as is the identification of both volatile (strain-switched) and nonvolatile (ferroelastic) regimes.

major comments (3)
  1. [first-principles calculations on Mn2SeO] The minimal tight-binding model and symmetry analysis demonstrate the AM-to-fFIM transition and full polarization under idealized uniaxial strain, but the first-principles section on Mn2SeO must explicitly show that ionic relaxation under the same strain does not reopen minority-spin states at the Fermi level or restore partial compensation (see the computational results for strained Mn2SeO).
  2. [Boltzmann transport theory] The Boltzmann transport results claim 100% spin polarization, yet it is unclear whether realistic Fermi-surface broadening, interband scattering, and higher-order hopping terms (beyond the minimal model) are retained; if these reduce polarization below unity, the headline claim of fully spin-polarized transport is weakened (see the transport theory subsection and associated figures).
  3. [V2SO results and ferroelastic discussion] For the ferroelastic fFIM candidate V2SO, the two symmetry-related states with opposite polarization are shown to be degenerate, but the energy barrier and switching pathway under orthogonal strain need quantitative evaluation to substantiate reversible spin switching (see the V2SO results and ferroelastic discussion).
minor comments (2)
  1. [symmetry analysis] Notation for the spin-group symmetries and the definition of the fFIM state should be made consistent between the symmetry analysis and the tight-binding Hamiltonian sections to avoid ambiguity.
  2. [figures] Figure captions for the band structures and conductivity plots should explicitly state the strain magnitude and direction used, and include the unstrained reference for direct comparison.

Simulated Author's Rebuttal

3 responses · 0 unresolved

We thank the referee for the positive evaluation of our manuscript and the constructive major comments. We address each point below, indicating where revisions will be made to strengthen the presentation.

read point-by-point responses

  1. Referee: [first-principles calculations on Mn2SeO] The minimal tight-binding model and symmetry analysis demonstrate the AM-to-fFIM transition and full polarization under idealized uniaxial strain, but the first-principles section on Mn2SeO must explicitly show that ionic relaxation under the same strain does not reopen minority-spin states at the Fermi level or restore partial compensation (see the computational results for strained Mn2SeO).

    Authors: We appreciate the referee highlighting this point for clarity. In our first-principles calculations for Mn2SeO, full ionic relaxation was performed under the applied uniaxial strain (using the same DFT settings as the unstrained case). The relaxed geometries preserve the induced sublattice inequivalence, and the spin-resolved bands confirm that minority-spin states remain gapped at the Fermi level with no restoration of partial compensation. To make this explicit, we will add a supplementary figure showing the relaxed atomic structures, strain-induced lattice parameters, and corresponding band structures for both orthogonal strain directions. revision: yes

  2. Referee: [Boltzmann transport theory] The Boltzmann transport results claim 100% spin polarization, yet it is unclear whether realistic Fermi-surface broadening, interband scattering, and higher-order hopping terms (beyond the minimal model) are retained; if these reduce polarization below unity, the headline claim of fully spin-polarized transport is weakened (see the transport theory subsection and associated figures).

    Authors: The transport calculations employ the semiclassical Boltzmann equation in the constant relaxation-time approximation applied to the tight-binding bands of the fFIM state. Full spin polarization is protected by the symmetry-enforced separation of spin channels, which forbids interband scattering between opposite spins. Fermi-surface broadening is incorporated via the smearing in the transport integrals, yet the polarization remains unity because no minority-spin states exist at the Fermi level. We acknowledge that higher-order hopping or strong scattering could introduce quantitative reductions in real materials; we will revise the transport subsection to state these approximations explicitly and add a brief discussion of robustness. revision: partial

  3. Referee: [V2SO results and ferroelastic discussion] For the ferroelastic fFIM candidate V2SO, the two symmetry-related states with opposite polarization are shown to be degenerate, but the energy barrier and switching pathway under orthogonal strain need quantitative evaluation to substantiate reversible spin switching (see the V2SO results and ferroelastic discussion).

    Authors: We agree that a quantitative energy barrier strengthens the claim of reversible switching. The manuscript demonstrates energetic degeneracy of the two fFIM states and their ferroelastic character. In the revision we will add nudged-elastic-band calculations (or equivalent) for the switching pathway between the orthogonal-strain variants of V2SO, reporting the barrier height under realistic strain magnitudes. This will be placed in the V2SO results section together with a short discussion of the switching energetics. revision: yes

Circularity Check

0 steps flagged

No significant circularity; symmetry and minimal model derivation is self-contained

full rationale

The paper derives the strain-induced altermagnetic to fully compensated ferrimagnetic transition and reversible spin polarization directly from symmetry analysis combined with a minimal tight-binding Hamiltonian. These inputs are general mathematical and physical principles independent of the target result. First-principles calculations on Mn2SeO and V2SO, plus Boltzmann transport, function as external verification on concrete candidates rather than as fitted parameters or self-definitions that force the outcome. No load-bearing self-citations, uniqueness theorems imported from the authors' prior work, or ansatzes smuggled via citation appear in the provided derivation chain. The argument therefore remains non-circular and externally falsifiable.

Axiom & Free-Parameter Ledger

0 free parameters · 2 axioms · 0 invented entities

The central claim rests on standard condensed-matter symmetry analysis and a minimal tight-binding model; no free parameters, ad-hoc axioms, or new invented entities are introduced in the abstract.

axioms (2)
  • domain assumption Symmetry constraints in altermagnets prevent net spin polarization in transport
    Invoked when stating that strain removes these constraints
  • domain assumption Uniaxial strain induces inequivalence between magnetic sublattices sufficient for full spin polarization
    Load-bearing step in the AM-to-fFIM transition

pith-pipeline@v0.9.0 · 5543 in / 1415 out tokens · 33170 ms · 2026-05-09T16:53:27.425264+00:00 · methodology

discussion (0)

Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.

Reference graph

Works this paper leans on

42 extracted references · 42 canonical work pages

  1. [1]

    ˇZuti´ c, J

    I. ˇZuti´ c, J. Fabian, and S. Das Sarma, Spintronics: Fundamen- tals and applications, Rev. Mod. Phys. 76, 323 (2004)

    work page 2004

  2. [2]

    Chappert, A

    C. Chappert, A. Fert, and F. N. V . Dau, The emergence of spin electronics in data storage, Nat. Mater. 6, 813 (2007)

    work page 2007

  3. [3]

    Z. Guo, X. Wang, W. Wang, G. Zhang, X. Zhou, and Z. Cheng, Spin-polarized antiferromagnets for spintronic s, Adv. Mater. 13, 2505779 (2025)

    work page 2025

  4. [4]

    Shao, S.-H

    D.-F. Shao, S.-H. Zhang, M. Li, C.-B. Eom, and E. Y . Tsymbal, Spin-neutral currents for spintronics, Nat. Commun. 12, 7061 (2021)

    work page 2021

  5. [5]

    Huang, P

    F.-F. Huang, P . Jiang, X. Zheng, H.-M. Huang, and Y .- L. Li, Emerging two-dimensional half-metal with high Curie temperature and strain-tunable altermagnetism, Phys. Rev. B 110, 174429 (2024)

    work page 2024

  6. [6]

    Baltz, A

    V . Baltz, A. Manchon, M. Tsoi, T. Moriyama, T. Ono, and Y . Tserkovnyak, Antiferromagnetic spintronics, Rev. Mod. Phys. 90, 015005 (2018)

    work page 2018

  7. [7]

    Jiang, L

    P . Jiang, L. Kang, H. Hao, X. Zheng, Z. Zeng, and S. Sanvito, Ferroelectric control of electron half-metallicity in A-type anti- ferromagnets and its application to nonvolatile memory devices, Phys. Rev. B 102, 245417 (2020) . 6

    work page 2020

  8. [8]

    Q. Chen, X. Zheng, P . Jiang, Y .-H. Zhou, L. Zhang, and Z. Zeng, Electric field induced tunable half- metallicity in an A-type antiferromagnetic bilayer LaBr 2, Phys. Rev. B 106, 245423 (2022)

    work page 2022

  9. [9]

    ˇSmejkal, J

    L. ˇSmejkal, J. Sinova, and T. Jungwirth, Beyond conven- tional ferromagnetism and antiferromagnetism: A phase with nonrelativistic spin and crystal rotation symmetry, Phys. Rev. X 12, 031042 (2022)

    work page 2022

  10. [10]

    Hayami, Y

    S. Hayami, Y . Yanagi, and H. Kusunose, Momentum- dependent spin splitting by collinear antiferromagnetic o rder- ing, J. Phys. Soc. Jpn. 88, 123702 (2019)

    work page 2019

  11. [11]

    Y uan, Z

    L.-D. Y uan, Z. Wang, J.-W. Luo, E. I. Rashba, and A. Zunger, Giant momentum-dependent spin splitting in centrosymmetr ic low-Z antiferromagnets, Phys. Rev. B 102, 014422 (2020)

    work page 2020

  12. [12]

    H.-Y . Ma, M. Hu, N. Li, J. Liu, W. Yao, J.-F. Jia, and J. Liu, Multifunctional antiferromagnetic materials with giant piezomagnetism and noncollinear spin current, Nat. Commun. 12, 2846 (2021)

    work page 2021

  13. [13]

    Osumi, S

    T. Osumi, S. Souma, T. Aoyama, K. Yamauchi, A. Honma, K. Nakayama, T. Takahashi, K. Ohgushi, and T. Sato, Ob- servation of a giant band splitting in altermagnetic MnTe, Phys. Rev. B 109, 115102 (2024)

    work page 2024

  14. [14]

    H. Bai, Y . C. Zhang, Y . J. Zhou, P . Chen, C. H. Wan, L. Han, W. X. Zhu, S. X. Liang, Y . C. Su, X. F. Han, F. Pan, and C. Song, E fficient spin-to-charge conversion via altermagnetic spin splitting e ffect in antiferromagnet RuO 2, Phys. Rev. Lett. 130, 216701 (2023)

    work page 2023

  15. [15]

    Reimers, L

    S. Reimers, L. Odenbreit, L. ˇSmejkal, V . N. Strocov, P . Con- stantinou, A. B. Hellenes, R. Jaeschke Ubiergo, W. H. Cam- pos, V . K. Bharadwaj, A. Chakraborty, et al. , Direct ob- servation of altermagnetic band splitting in CrSb thin films , Nat. Commun. 15, 2116 (2024)

    work page 2024

  16. [16]

    Zhang, P

    X. Zhang, P . Jiang, L.-Y . Xu, L. Wang, L. Liu, H.- M. Huang, T. Cao, and Y .-L. Li, Giant spin splitting and anisotropic spin Polarization in 2D altermagnet Cr 2O, Nano Lett. 25, 16547 (2025)

    work page 2025

  17. [17]

    X. Duan, J. Zhang, Z. Zhu, Y . Liu, Z. Zhang, I. ˇZuti´ c, and T. Zhou, Antiferroelectric altermagnets: Antiferroelect ricity al- ters magnets, Phys. Rev. Lett. 134, 106801 (2025)

    work page 2025

  18. [18]

    Z. Zhu, X. Duan, J. Zhang, B. Hao, I. ˇZuti´ c, and T. Zhou, Two- dimensional ferroelectric altermagnets: From model to mat erial realization, Nano Lett. 25, 9456 (2025)

    work page 2025

  19. [19]

    C. Song, H. Bai, Z. Zhou, L. Han, H. Reichlova, J. H. Dil, J. Liu, X. Chen, and F. Pan, Altermagnets as a new class of functional materials, Nat. Rev. Mater. 10, 473 (2025)

    work page 2025

  20. [20]

    M. Dou, X. Wang, and L. L. Tao, Anisotropic spin- polarized conductivity in collinear altermagnets, Phys. Rev. B 111, 224423 (2025)

    work page 2025

  21. [21]

    Zhang, Z.-A

    S.-S. Zhang, Z.-A. Wang, B. Li, W.-J. Lu, M. Tian, Y .- P . Sun, H. Du, and D.-F. Shao, Deterministic switch- ing of the N´ eel vector by asymmetric spin torque, Phys. Rev. Lett. 136, 096702 (2026)

    work page 2026

  22. [22]

    L. Han, X. Fu, R. Peng, X. Cheng, J. Dai, L. Liu, Y . Li, Y . Zhang, W. Zhu, H. Bai, Y . Zhou, S. Liang, C. Chen, Q. Wang, X. Chen, L. Yang, Y . Zhang, C. Song, J. Liu, and F. Pan, Elec- trical 180° switching of N´ eel vector in spin-splitting ant iferro- magnet, Sci. Adv. 10, eadn0479 (2024)

    work page 2024

  23. [23]

    S. Y . Bodnar, L. ˇSmejkal, I. Turek, T. Jungwirth, O. Gomonay, J. Sinova, A. Sapozhnik, H.-J. Elmers, M. Kl¨ aui, and M. Jour - dan, Writing and reading antiferromagnetic Mn 2Au by N´ eel spin-orbit torques and large anisotropic magnetoresistan ce, Nat. Commun. 9, 348 (2018)

    work page 2018

  24. [24]

    Cheng, S

    Y . Cheng, S. Y u, M. Zhu, J. Hwang, and F. Yang, Electrical switching of tristate antiferromagnetic N´ eel order in α−Fe2O3 epitaxial films, Phys. Rev. Lett. 124, 027202 (2020)

    work page 2020

  25. [25]

    Zhang, C

    R.-W. Zhang, C. Cui, R. Li, J. Duan, L. Li, Z.-M. Y u, and Y . Yao, Predictable gate-field control of spin in altermagne ts with spin-layer coupling, Phys. Rev. Lett. 133, 056401 (2024)

    work page 2024

  26. [26]

    S.-D. Guo, Q. Luo, S.-H. Zhang, and P . Jiang, Exter- nal field induced transition from altermagnetic metal to fully compensated ferrimagnetic metal in monolayer Cr 2O, Phys. Rev. B 113, 064408 (2026)

    work page 2026

  27. [27]

    S.-D. Guo, S. Chen, and G. Wang, Spin ordering induced fully compensated ferrimagnetism achieved in bilayers of Cr 2C2S6, Phys. Rev. B 112, 134430 (2025)

    work page 2025

  28. [28]

    Huang, C

    Y . Huang, C. Hua, R. Xu, J. Liu, Y . Zheng, and Y . Lu, Spin in- version enforced by crystal symmetry in ferroelastic alter mag- nets, Phys. Rev. Lett. 135, 266701 (2025)

    work page 2025

  29. [29]

    D. Guo, J. Dai, R. Wang, C. Wang, and W. Ji, Mechanically and electrically switchable triferroic altermagnet in a pe ntago- nal FeO2 monolayer, Phys. Rev. B 112, 195410 (2025)

    work page 2025

  30. [30]

    N. Ding, H. Ye, S.-S. Wang, and S. Dong, Ferroelastically tun - able altermagnets, Phys. Rev. B 112, L220410 (2025)

    work page 2025

  31. [31]

    Huang, S

    F. Huang, S. He, K.-Q. Chen, and L.-M. Tang, Spin-ferroelasticity coupling in nonrelativistic spin-split antiferromagnetic-ferroelastic systems, Phys. Rev. B 113, L020411 (2026)

    work page 2026

  32. [32]

    R. Peng, S. Fang, P . Ho, F. Liu, T. Zhou, J. Liu, and Y . S. Ang, Ferroelastic altermagnetism, npj Quantum Mater. 11, 5 (2026)

    work page 2026

  33. [33]

    Liu, S.-D

    Y . Liu, S.-D. Guo, Y . Li, and C.-C. Liu, Two- dimensional fully compensated ferrimagnetism, Phys. Rev. Lett. 134, 116703 (2025)

    work page 2025

  34. [34]

    Jiang, X

    P . Jiang, X. Tao, H. Hao, Y . Liu, X. Zheng, and Z. Zeng, Two- dimensional centrosymmetrical antiferromagnets for spin pho- togalvanic devices, npj Quantum Inf. 7, 21 (2021)

    work page 2021

  35. [35]

    L. Liu, P . Jiang, H.-M. Huang, and Y .-L. Li, Electrostatic doping tunable magnetic transition and half-metallicity in the monolayer CrCTe 3, J. Phys.: Conden. Matter 36, 355803 (2024)

    work page 2024

  36. [36]

    Li and J

    X. Li and J. Yang, First-principles design of spintronics ma teri- als, Natl. Sci. Rev 3, 365 (2016)

    work page 2016

  37. [37]

    Z. Guo, S. Qian, X. Zhou, W. Wang, Z. Cheng, and X. Wang, Sliding ferroelectric metal with ferrimagnetism, Nat. Commun. 17, 549 (2026)

    work page 2026

  38. [38]

    J. Gong, Y . Yang, J. Bai, W. Wang, S. Qian, X. Zhou, and Z. Cheng, Triply-coupled switching in 2D ferroelastic ferrimag- netic metals, Adv. Funct. Mater. 36, e25986 (2026)

    work page 2026

  39. [39]

    see supplementary material at *** /****

    work page

  40. [40]

    L.-Y . Xu, P . Jiang, L. Liu, H.-M. Huang, and Y .-L. Li, Strain- tunable magnetic phase transition and magnetocaloric e ffect in the CrS 2 monolayer with bipolar magnetic semiconducting characteristics, Phys. Rev. B 111, 205407 (2025)

    work page 2025

  41. [41]

    X. Tao, P . Jiang, H. Hao, X. Zheng, L. Zhang, and Z. Zeng, Pure spin current generation via photogalvanic e ffect with spatial in- version symmetry, Phys. Rev. B 102, 081402 (2020)

    work page 2020

  42. [42]

    Jiang, L

    S. Jiang, L. Li, Z. Wang, K. F. Mak, and J. Shan, Controlling magnetism in 2D CrI 3 by electrostatic doping, Nat. Nanotechnol. 13, 549 (2018)

    work page 2018