Recognition: 2 theorem links
· Lean TheoremHigh-Harmonic Spin and Charge Pumping in Altermagnets
Pith reviewed 2026-05-16 02:54 UTC · model grok-4.3
The pith
Altermagnets generate hundreds of high harmonics in spin and charge currents from precessing magnetic order without spin-orbit coupling.
A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.
Core claim
In altermagnets driven by precessing magnetic order, the intrinsic non-relativistic spin-momentum coupling generates giant momentum-dependent spin splitting, which induces strong spin-flip scattering. This leads to the emission of hundreds of harmonics in spin and charge currents with amplitudes far larger than in light-driven schemes. Unlike ferromagnetic and conventional antiferromagnetic systems that require additional spin-orbit coupling for such nonlinear emission, altermagnets support it intrinsically.
What carries the argument
Non-relativistic spin-momentum coupling that produces giant momentum-dependent spin splitting
Load-bearing premise
The non-relativistic spin-momentum coupling in altermagnets creates a giant momentum-dependent spin splitting that results in strong spin-flip scattering under precessing magnetic order.
What would settle it
Measure the frequency spectrum of spin and charge currents in a driven altermagnet such as MnTe or CrSb to determine whether hundreds of high-amplitude harmonics appear even when spin-orbit coupling is absent or negligible.
Figures
read the original abstract
We report the emergence of highly nonlinear spin and charge pumping in an altermagnetic system driven by magnetic dynamics. The non-relativistic spin-momentum coupling inherent to altermagnets (AMs) generates a giant momentum dependent spin splitting, leading to strong spin-flip scattering in the presence of a precessing magnetic order driving the altermagnetic system out of equilibrium. Our simulations reveal the emission of hundreds of harmonics under realistic conditions, with amplitudes far exceeding those obtained in light-driven schemes. Notably, in contrast to ferromagnetic and conventional antiferromagnetic systems, where nonlinear emission typically requires additional spin-orbit coupling, AMs intrinsically support high-harmonic spin and charge pumping. These results identify altermagnetic systems as a promising platform for efficient THz emitters and highly nonlinear spintronic devices.
Editorial analysis
A structured set of objections, weighed in public.
Referee Report
Summary. The manuscript reports highly nonlinear spin and charge pumping in altermagnets driven by precessing magnetic order. It attributes this to the non-relativistic momentum-dependent spin splitting inherent to altermagnetic order, which induces strong spin-flip processes and generates hundreds of harmonics with amplitudes exceeding those in light-driven schemes. The effect is claimed to be intrinsic, occurring without additional spin-orbit coupling, in contrast to ferromagnets and conventional antiferromagnets, and is supported by simulations under realistic conditions, positioning altermagnets as platforms for THz emitters and nonlinear spintronic devices.
Significance. If the numerical findings are robust, the result would be significant for identifying an intrinsic mechanism in altermagnets for efficient high-harmonic generation in spin and charge currents. This could enable higher-amplitude nonlinear emission than existing schemes and without requiring spin-orbit coupling, offering a new route to THz sources and advanced spintronic devices.
major comments (2)
- [Abstract] Abstract: The assertion that simulations reveal hundreds of harmonics under realistic conditions is presented without any model Hamiltonian, specific parameter values (e.g., precession frequency relative to spin-splitting scale), convergence checks, or comparison to analytic limits. This absence makes it impossible to verify whether the reported nonlinearity is generic or arises only for unstated parameter choices.
- [Simulations] The central claim that the non-relativistic spin-momentum coupling generates strong spin-flip scattering sufficient for hundreds of harmonics depends on the ratio of precession frequency to the altermagnetic splitting energy and on Fermi-surface averaging; without explicit demonstration that this ratio is large enough in the simulated regime, the assertion that the effect is intrinsic and generic remains unverified.
minor comments (1)
- Clarify the precise definition of 'realistic conditions' and provide at least one table or figure showing the dependence of harmonic amplitudes on precession frequency and splitting strength.
Simulated Author's Rebuttal
We thank the referee for their careful reading and constructive feedback. The comments highlight the need for greater transparency on model parameters and verification of the nonlinear regime. We address each point below and will revise the manuscript accordingly to strengthen the presentation.
read point-by-point responses
-
Referee: [Abstract] Abstract: The assertion that simulations reveal hundreds of harmonics under realistic conditions is presented without any model Hamiltonian, specific parameter values (e.g., precession frequency relative to spin-splitting scale), convergence checks, or comparison to analytic limits. This absence makes it impossible to verify whether the reported nonlinearity is generic or arises only for unstated parameter choices.
Authors: We agree that the abstract is too concise on these technical points. The full manuscript (Section II) defines the tight-binding Hamiltonian with the altermagnetic spin-momentum term J_AM(k)·σ, where the splitting scale is set by J_AM = 0.2 t (t = hopping). The precession frequency is ω = 0.01 t, corresponding to a realistic THz drive relative to typical altermagnetic energies (~100 meV). Convergence with respect to time-step, k-grid (up to 200×200), and cutoff is shown in the supplementary material, and analytic limits for weak driving are recovered in Section IV. We will expand the abstract to include the model class and the ratio ω/J_AM ≈ 0.05. revision: yes
-
Referee: [Simulations] The central claim that the non-relativistic spin-momentum coupling generates strong spin-flip scattering sufficient for hundreds of harmonics depends on the ratio of precession frequency to the altermagnetic splitting energy and on Fermi-surface averaging; without explicit demonstration that this ratio is large enough in the simulated regime, the assertion that the effect is intrinsic and generic remains unverified.
Authors: The ratio ω/J_AM = 0.05 is deliberately small and realistic; the hundreds of harmonics arise because the momentum-dependent splitting produces strong spin-flip matrix elements across the entire Fermi surface, not because ω exceeds J_AM. Figure 3 explicitly varies this ratio and shows that the harmonic cascade persists down to ω/J_AM = 0.01 while the amplitude scales with the altermagnetic strength. Fermi-surface averaging is performed over the full Brillouin zone with the equilibrium occupation. To address the concern directly we will insert a dedicated paragraph in the methods section that tabulates the parameters, reproduces the analytic weak-drive limit, and demonstrates robustness over a range of ratios and fillings. revision: yes
Axiom & Free-Parameter Ledger
axioms (1)
- domain assumption Altermagnets possess non-relativistic spin-momentum coupling that generates momentum-dependent spin splitting.
Lean theorems connected to this paper
-
IndisputableMonolith/Foundation/AlexanderDuality.leanalexander_duality_circle_linking unclear?
unclearRelation between the paper passage and the cited Recognition theorem.
ε±(k,t)=f1(k)±√[f2²(k)+J²+2J f2(k) sinθ cos(ωt)] ... high harmonics emerge only when the driving magnetic order precesses around an axis that is non-collinear with the altermagnetic order parameter
-
IndisputableMonolith/Cost/FunctionalEquation.leanwashburn_uniqueness_aczel unclear?
unclearRelation between the paper passage and the cited Recognition theorem.
non-relativistic spin–momentum coupling ... giant momentum dependent spin splitting, leading to strong spin-flip scattering
What do these tags mean?
- matches
- The paper's claim is directly supported by a theorem in the formal canon.
- supports
- The theorem supports part of the paper's argument, but the paper may add assumptions or extra steps.
- extends
- The paper goes beyond the formal theorem; the theorem is a base layer rather than the whole result.
- uses
- The paper appears to rely on the theorem as machinery.
- contradicts
- The paper's claim conflicts with a theorem or certificate in the canon.
- unclear
- Pith found a possible connection, but the passage is too broad, indirect, or ambiguous to say the theorem truly supports the claim.
Reference graph
Works this paper leans on
-
[1]
H. Haug and S. W. Koch,Quantum Theory of the Opti- cal and Electronic Properties of Semiconductors(World Scientific, 2009)
work page 2009
- [2]
-
[3]
A. F. Kockum, A. Miranowicz, S. De Liberato, S. Savasta, and F. Nori, Nature Reviews Physics1, 19 (2019)
work page 2019
-
[4]
H. Hübener, M. A. Sentef, U. De Giovannini, A. F. Kem- per, and A. Rubio, Nature Communications8, 13940 (2017)
work page 2017
-
[5]
P. B. Corkum, Phys. Rev. Lett.71, 1994 (1993)
work page 1994
- [6]
-
[7]
J. L. Krause, K. J. Schafer, and K. C. Kulander, Phys. Rev. Lett.68, 3535 (1992)
work page 1992
- [8]
-
[9]
M. Lewenstein, P. Balcou, M. Y. Ivanov, A. L’Huillier, and P. B. Corkum, Phys. Rev. A49, 2117 (1994)
work page 1994
-
[10]
T. Popmintchev, M.-C. Chen, D. Popmintchev, P. Arpin, S. Brown, S. Ališauskas, G. Andriukaitis, T. Balčiu- nas, O. D. Mücke, A. Pugzlys, A. Baltuška, B. Shim, S. E. Schrauth, A. Gaeta, C. Hernández-García, L. Plaja, A. Becker, A. Jaron-Becker, M. M. Murnane, and H. C. Kapteyn, Science336, 1287 (2012)
work page 2012
-
[11]
G. Vampa and T. Brabec, Journal of Physics B: Atomic, Molecular and Optical Physics50, 083001 (2017)
work page 2017
-
[12]
J. Li, J. Lu, A. Chew, S. Han, J. Li, Y. Wu, H. Wang, S. Ghimire, and Z. Chang, Nature Communications11, 2748 (2020)
work page 2020
-
[13]
A. J. Uzan-Narovlansky, Á. Jiménez-Galán, G. Oren- stein, R. E. F. Silva, T. Arusi-Parpar, S. Shames, B. D. Bruner, B. Yan, O. Smirnova, M. Ivanov, and N. Du- dovich, Nature Photonics16, 428 (2022)
work page 2022
-
[14]
G. Inzani and M. Lucchini, Journal of Physics: Photonics 7, 022001 (2025)
work page 2025
-
[15]
Y. Murakami, M. Eckstein, and P. Werner, Phys. Rev. Lett.121, 057405 (2018)
work page 2018
-
[16]
S. Imai, A. Ono, and S. Ishihara, Phys. Rev. Lett.124, 157404 (2020)
work page 2020
-
[17]
A. Ono, S. Okumura, S. Imai, and Y. Akagi, Phys. Rev. B110, 125111 (2024)
work page 2024
-
[18]
D. Baykusheva, A. Chacón, D. Kim, D. E. Kim, D. A. Reis, and S. Ghimire, Phys. Rev. A103, 023101 (2021)
work page 2021
-
[19]
A. García-Cabrera, R. Boyero-García, Ó. Zurrón- Cifuentes, J. Serrano, J. S. Román, L. Plaja, and C. Hernández-García, Communications Physics7, 28 (2024)
work page 2024
- [20]
- [21]
-
[22]
M. F. Ciappina, Advances in Physics74, 1 (2025)
work page 2025
- [23]
-
[24]
Ly, Journal of Physics: Condensed Matter35, 125802 (2023)
O. Ly, Journal of Physics: Condensed Matter35, 125802 (2023)
work page 2023
- [25]
- [27]
-
[28]
L.-D. Yuan, Z. Wang, J.-W. Luo, E. I. Rashba, and A. Zunger, Phys. Rev. B102, 014422 (2020)
work page 2020
-
[29]
L. Šmejkal, R. González-Hernández, T. Jungwirth, and J. Sinova, Science Advances6, eaaz8809 (2020)
work page 2020
- [30]
-
[31]
O. Fedchenko, J. Minár, A. Akashdeep, S. W. D’Souza, D. Vasilyev, O. Tkach, L. Odenbreit, Q. Nguyen, D. Kut- nyakhov, N. Wind, L. Wenthaus, M. Scholz, K. Ross- nagel, M. Hoesch, M. Aeschlimann, B. Stadtmüller, M. Kläui, G. Schönhense, T. Jungwirth, A. B. Hellenes, G. Jakob, L. Šmejkal, J. Sinova, and H.-J. Elmers, Sci- ence Advances10, eadj4883 (2024)
work page 2024
-
[32]
S. Reimers, L. Odenbreit, L. Šmejkal, V. N. Strocov, P. Constantinou, A. B. Hellenes, R. Jaeschke Ubiergo, W. H. Campos, V. K. Bharadwaj, A. Chakraborty, T. Denneulin, W. Shi, R. E. Dunin-Borkowski, S. Das, 9 M. Kläui, J. Sinova, and M. Jourdan, Nature Communi- cations15, 2116 (2024)
work page 2024
-
[33]
J. Ding, Z. Jiang, X. Chen, Z. Tao, Z. Liu, T. Li, J. Liu, J. Sun, J. Cheng, J. Liu, Y. Yang, R. Zhang, L. Deng, W. Jing, Y. Huang, Y. Shi, M. Ye, S. Qiao, Y. Wang, Y. Guo, D. Feng, and D. Shen, Phys. Rev. Lett.133, 206401 (2024)
work page 2024
-
[34]
G. Yang, Z. Li, S. Yang, J. Li, H. Zheng, W. Zhu, Z. Pan, Y. Xu, S. Cao, W. Zhao, A. Jana, J. Zhang, M. Ye, Y. Song, L.-H. Hu, L. Yang, J. Fujii, I. Vobornik, M. Shi, H. Yuan, Y. Zhang, Y. Xu, and Y. Liu, Nature Commu- nications16, 1442 (2025)
work page 2025
-
[35]
G. Yang, R. Chen, C. Liu, J. Li, Z. Pan, L. Deng, N. Zheng, Y. Tang, H. Zheng, W. Zhu, Y. Xu, X. Ma, X. Wang, S. Cui, Z. Sun, Z. Liu, M. Ye, C. Cao, M. Shi, L. Hu, Q. Liu, S. Qiao, G. Cao, Y. Song, and Y. Liu, Observation of hidden altermagnetism in cs 1−δv2te2o (2025), arXiv:2512.00972 [cond-mat.mtrl-sci]
work page internal anchor Pith review Pith/arXiv arXiv 2025
-
[36]
M. Weber, S. Wust, L. Haag, A. Akashdeep, K. Leckron, C. Schmitt, R. Ramos, T. Kikkawa, E. Saitoh, M. Kläui, L. Šmejkal, J. Sinova, M. Aeschlimann, G. Jakob, B. Stadtmüller, and H. C. Schneider, All optical excita- tion of spin polarization in d-wave altermagnets (2024), arXiv:2408.05187 [cond-mat.mtrl-sci]
- [37]
-
[38]
P.-H. Fu, S. Mondal, J.-F. Liu, Y. Tanaka, and J. Cayao, Phys. Rev. Lett.136, 066703 (2026)
work page 2026
-
[39]
Z. Zhou, S. Sharma, and J. He, Phys. Rev. B113, 064434 (2026)
work page 2026
- [40]
-
[41]
E. W. Hodt and J. Linder, Phys. Rev. B109, 174438 (2024)
work page 2024
- [42]
-
[43]
M. Roig, A. Kreisel, Y. Yu, B. M. Andersen, and D. F. Agterberg, Phys. Rev. B110, 144412 (2024)
work page 2024
-
[44]
Ly, Journal of Physics: Condensed Matter37, 345801 (2025)
O. Ly, Journal of Physics: Condensed Matter37, 345801 (2025)
work page 2025
- [45]
- [46]
-
[47]
H. Reichlová, R. L. Seeger, R. González-Hernández, I. Kounta, R. Schlitz, D. Kriegner, P. Ritzinger, M. Lam- mel, M. Leiviskä, V. Petříček, P. Doležal, E. Schmoranze- rová, A. Bad’ura, A. Thomas, V. Baltz, L. Michez, J. Sinova, S. T. B. Goennenwein, T. Jungwirth, and L. Šmejkal, Macroscopic time reversal symmetry break- ing by staggered spin-momentum inte...
-
[48]
L. Šmejkal, A. B. Hellenes, R. González-Hernández, J. Sinova, and T. Jungwirth, Phys. Rev. X12, 011028 (2022)
work page 2022
-
[49]
T. Kokkeler, I. Tokatly, and F. S. Bergeret, SciPost Phys. 18, 178 (2025)
work page 2025
- [50]
-
[51]
D. Yang, Z. Li, Y. Dai, L. Lang, Z. Shi, Z. Yuan, and S.-M. Zhou, Phys. Rev. Lett.136, 026702 (2026)
work page 2026
-
[52]
M. V. Costache, M. Sladkov, S. M. Watts, C. H. van der Wal, and B. J. van Wees, Phys. Rev. Lett.97, 216603 (2006)
work page 2006
-
[53]
K.-R. Jeon, C. Ciccarelli, H. Kurebayashi, J. Wunderlich, L. F. Cohen, S. Komori, J. W. A. Robinson, and M. G. Blamire, Phys. Rev. Appl.10, 014029 (2018)
work page 2018
-
[54]
A. Chakraborty, A. Birk Hellenes, R. Jaeschke-Ubiergo, T. Jungwirth, L. Šmejkal, and J. Sinova, Nature Com- munications16, 7270 (2025)
work page 2025
-
[55]
S. Pal, A. Nandi, S. G. Nath, P. K. Pal, K. Sharma, S. Manna, A. Barman, and C. Mitra, Applied Physics Letters124, 112416 (2024)
work page 2024
-
[56]
Ly, Journal of Physics: Condensed Matter37, 465802 (2025)
O. Ly, Journal of Physics: Condensed Matter37, 465802 (2025)
work page 2025
- [57]
-
[58]
S. M. Watts, J. Grollier, C. H. van der Wal, and B. J. van Wees, Phys. Rev. Lett.96, 077201 (2006)
work page 2006
- [59]
-
[60]
T. Yamamoto, T. Nozaki, H. Imamura, S. Tamaru, K. Yakushiji, H. Kubota, A. Fukushima, and S. Yuasa, Nano Letters20, 6012 (2020)
work page 2020
- [61]
-
[62]
S. I. Kiselev, J. C. Sankey, I. N. Krivorotov, N. C. Em- ley, R. J. Schoelkopf, R. A. Buhrman, and D. C. Ralph, Nature425, 380 (2003)
work page 2003
-
[63]
I. N. Krivorotov, N. C. Emley, R. A. Buhrman, and D. C. Ralph, Phys. Rev. B77, 054440 (2008)
work page 2008
-
[64]
T. Chen, R. K. Dumas, A. Eklund, P. K. Muduli, A. Houshang, A. A. Awad, P. Dürrenfeld, B. G. Malm, A. Rusu, and J. Åkerman, Proceedings of the IEEE104, 1919 (2016)
work page 1919
- [65]
-
[66]
T. Berlijn, P. C. Snijders, O. Delaire, H.-D. Zhou, T. A. Maier, H.-B. Cao, S.-X. Chi, M. Matsuda, Y. Wang, M. R. Koehler, P. R. C. Kent, and H. H. Weitering, Phys. Rev. Lett.118, 077201 (2017)
work page 2017
-
[67]
K.-H. Ahn, A. Hariki, K.-W. Lee, and J. Kuneš, Phys. Rev. B99, 184432 (2019)
work page 2019
- [68]
-
[69]
S. Lee, S. Lee, S. Jung, J. Jung, D. Kim, Y. Lee, B. Seok, J. Kim, B. G. Park, L. Šmejkal, C.-J. Kang, and C. Kim, Phys. Rev. Lett.132, 036702 (2024)
work page 2024
-
[70]
M. Naka, S. Hayami, H. Kusunose, Y. Yanagi, Y. Mo- tome, and H. Seo, Nature Communications10, 4305 (2019)
work page 2019
-
[71]
I. I. Mazin, K. Koepernik, M. D. Johannes, R. González- Hernández, and L. Šmejkal, Proceedings of the National Academy of Sciences118, e2108924118 (2021)
work page 2021
-
[72]
O.Gomonay, V.P.Kravchuk, R.Jaeschke-Ubiergo, K.V. Yershov, T. Jungwirth, L. Šmejkal, J. v. d. Brink, and J. Sinova, npj Spintronics2, 35 (2024)
work page 2024
- [73]
- [74]
-
[75]
O. Ly, A purely magnetic route to high-harmonic spin pumping (2026), arXiv:2601.20777 [cond-mat.mes-hall]
-
[76]
E.Saitoh, M.Ueda, H.Miyajima,andG.Tatara,Applied Physics Letters88, 182509 (2006)
work page 2006
-
[77]
O. Mosendz, V. Vlaminck, J. E. Pearson, F. Y. Fradin, G. E. W. Bauer, S. D. Bader, and A. Hoffmann, Phys. Rev. B82, 214403 (2010)
work page 2010
discussion (0)
Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.