Pith. sign in

REVIEW 2 major objections 5 minor 83 references

Probing broken time-reversal symmetry with tailored-light photocurrents

T0 review · 2 major / 5 minor · reviewed 2026-08-06 · deepseek-v4-flash

Pith's one-line read A pair of linearly polarized laser beams, with a fixed relative phase, can detect broken time-reversal symmetry in a material without circular polarization or magnetic fields.

desk verdict A strong symmetry-based photocurrent probe of TRS breaking, but the printed field definition contradicts the TRS claim and must be fixed. read the letter →

arxiv 2507.05768 v2 pith:7MMDWRPS submitted 2025-07-08 physics.optics cond-mat.mtrl-sci

classification physics.opticscond-mat.mtrl-sci
keywords bulkphotogalvaniceffecttime-reversalsymmetrybichromaticlaserfieldsphotocurrentselectionrulesmonolayergrapheneCrI3FloquetCherninsulatorultrafastspectroscopy
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

The paper claims that a tailored two-color field, two linearly polarized beams at frequencies $\omega$ and $2\omega$, can act as a time-reversal-respecting probe of materials. When the relative phase between the two colors is $\pi/2$, the combined field is said to preserve time-reversal symmetry while breaking every spatial symmetry of the crystal, and in such a field a bulk photocurrent must vanish in any time-reversal-invariant material. The authors demonstrate this suppression experimentally in monolayer graphene and reproduce it with ab initio time-dependent density functional theory. They then predict that the suppression disappears in the ferromagnet CrI$_3$ and in a Floquet Chern insulator, where the material itself breaks time reversal. The practical payoff is an ultrafast, background-free photocurrent signature of magnetism and topological order that does not require the probe to break time-reversal symmetry itself.

What carries the argument

The load-bearing object is the bichromatic $\omega$-$2\omega$ field with two continuously tunable dials, the relative polarization angle $\theta$ and the two-color phase $\phi$, whose Lissajous figure is classified by mirror symmetry and time-reversal symmetry. At $\theta=90^\circ$ the field has a dynamical mirror symmetry that suppresses photocurrent for all phases; at $\phi=\pi/2$ the paper asserts the field preserves time reversal for every $\theta$, so the suppression at that phase is attributed to time-reversal symmetry alone. The argument is carried by the $\mathbf{k}$ versus $-\mathbf{k}$ cancellation: because time reversal connects Bloch states as $\psi_{\mathbf{k}}=\psi^*_{-\mathbf{k}}$, a time-reversal-preserving drive excites equal carrier populations at $\mathbf{k}$ and $-\mathbf{k}$, and their velocities cancel, giving zero net current. Reversing the logic turns the null line into a diagnostic: any current measured at the time-reversal-respecting phase means the material's own time-reversal symmetry is broken.

What would settle it

Measure the $\phi=\pi/2$ photocurrent in a known time-reversal-invariant material at a generic angle such as $\theta=135^\circ$: the selection rule predicts an exact zero, so any current above the noise floor at that point would falsify it. Separately, compute the time-reversed field from the Methods vector potential at $\theta=135^\circ$, $\phi=\pi/2$: the x-component is proportional to $\sin(2\omega t)$ and is odd under $t\to -t$, so deciding whether the full light-matter Hamiltonian is invariant under pure time reversal or only under a mirror-time-reversal combination determines whether the observed suppression is a genuine time-reversal selection rule.

Watch

Extended reading notes

Core claim

The central discovery is a forbidden-current selection rule: in a time-reversal-invariant system, an $\omega$-$2\omega$ field built from two linearly polarized components generates no bulk photogalvanic current when the relative phase is $\phi=\pi/2$, irrespective of the relative polarization angle $\theta$. The mechanism is that at this phase the tailored field is claimed to satisfy $\mathbf{E}(t)=\mathbf{E}(-t)$ while having no remaining spatial symmetry; time-reversal invariance of the full light-matter Hamiltonian then forces equal excitation at $\mathbf{k}$ and $-\mathbf{k}$, and the electron velocities cancel pairwise. The paper reports the first experimental observation of this TRS-induced suppression, mapped as a full zero-current line at $\phi=\pi/2$ in monolayer graphene. In ab initio simulations, the same line is absent in CrI$_3$ and in a Floquet Chern insulator: nonzero current appears at the symmetry-respecting phase, and its size and the shift of its minimum track the degree of broken time reversal and the topological gap.

Load-bearing premise

The argument depends on the assertion that at a two-color phase of $\pi/2$ the tailored field truly respects time-reversal symmetry for every relative polarization angle, but the Methods field formula at 135 degrees has an x-component proportional to $\sin(2\omega t)$, which changes sign when time runs backwards, so if the real symmetry is only a mirror combined with time reversal, the central selection rule is not a pure time-reversal effect.

Editorial extensions

If this is right

  • A null photocurrent at $\phi=\pi/2$ for all $\theta$ diagnoses a time-reversal-invariant sample, while a nonzero current at that point flags broken time reversal, with the magnitude and phase shift of the minimum encoding how strongly the symmetry is broken.
  • Because the probe is linearly polarized and time-reversal-respecting, magnetic order can be detected without circularly polarized light or external magnetic fields, and the measurement can in principle be resolved on the femtosecond timescale.
  • In the 2D ferromagnet CrI$_3$ the predicted photocurrent minimum shifts from $\phi=\pi/2$ to $\phi=0$ and never reaches zero, giving a material-specific signature of intrinsic magnetism.
  • In Floquet Chern insulators the minimum shifts away from $\pi/2$ and its dressing-intensity dependence tracks the topological gap and Berry curvature, making the method an all-optical readout of dressed topological states.
  • Because the observable is an accumulating dc current, the technique should be less sensitive to electron decoherence and phase-matching than coherent optical probes of the same symmetries.

Reading between the lines

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

  • The authors leave implicit that the same $\phi=\pi/2$ cancellation should apply to any injection-current observable, such as terahertz emission, valley-selective carrier populations, or ballistic currents, so the selection rule could be ported to other ultrafast detectors beyond dc transport.
  • An extension worth testing is whether the sign of the residual current at the symmetry-respecting phase encodes the sign of the time-reversal breaking, such as the magnetization direction or the Chern number, which would give a helicity-free magnetic contrast mechanism.
  • Because the symmetry argument only uses $\mathbf{k}\leftrightarrow -\mathbf{k}$ cancellation under time reversal, it should generalize beyond hexagonal two-dimensional lattices to any inversion- and time-reversal-preserving band structure, including bulk three-dimensional materials.
  • One point the authors do not settle explicitly is the exact symmetry operation at $\theta=135^\circ$, $\phi=\pi/2$: the Methods vector potential has an x-component $\propto \sin(2\omega t)$, which is odd under $t\to -t$, so identifying whether the relevant symmetry is pure time reversal or a combined mirror-time-reversal operation would sharpen the interpretation of the CrI$_3$ and Floquet results
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

2 major / 5 minor

Summary. The paper proposes a symmetry-based spectroscopic scheme to detect broken time-reversal symmetry (TRS) in solids using bichromatic ω−2ω linearly polarized laser fields. The central claim is that for a relative phase φω−2ω = π/2 and arbitrary angle θω−2ω between the two polarizations, the tailored field preserves TRS while breaking all other spatial symmetries, which imposes a photocurrent selection rule in TRS-invariant materials. The authors present experimental photocurrent maps in graphene showing suppression at this phase, corroborated by TDDFT simulations and an analytical k-space population argument. They further predict that the selection rule breaks in CrI3 and in a circularly dressed graphene Floquet Chern insulator, offering a background-free ultrafast probe of magnetism and topological phases.

Significance. If the central classification is correct, the work introduces a genuinely new type of symmetry-breaking spectroscopy: it claims to detect broken TRS with a probe that itself does not break TRS, avoiding circular polarization and external magnetic fields. The k-space injection-current argument is clean, and the qualitative agreement between the TDDFT simulations and the measured graphene photocurrent maps is encouraging. The proposal's potential reach is broad, extending to ultrafast magnetism and Floquet engineering. The paper also benefits from being built on reproducible ab initio methods (Octopus) and transparent symmetry reasoning. However, the significance is contingent on resolving a concrete inconsistency in the field definition (see Major Comment 1).

major comments (2)
  1. [Methods, Eq. (2)] The printed vector potential, A(t) ∝ cos(ωt+φ) ŷ + (Δ/2)(cosθ cos(2ωt) x̂ + sinθ sin(2ωt) ŷ), contradicts the central claim that the φ=π/2 configuration preserves TRS for all θ. With φ=π/2, the electric field E(t) = −∂A/∂t has E_x ∝ cosθ sin(2ωt), which is odd under t→−t, so E(t)≠E(−t) unless cosθ=0. Moreover, the 2ω part is elliptically polarized (x and y components in quadrature), contradicting the statement in the same Methods section that the beams are linearly polarized at all configurations. Because the entire interpretation of Fig. 2b(ii), Fig. 3b,d, and Fig. 4 rests on the TRS property of this waveform, the authors must either correct Eq. (2) to a form in which both 2ω components share the same time dependence (e.g., both proportional to cos(2ωt) or both to sin(2ωt)), or show explicitly that the simulations and experiment used a different field than the one printed. Without this clarification, the experimental suppression cannot be attributed to a TRS selection rule.
  2. [Results, Fig. 2a,b] The central experimental observation is a null result: the photocurrent is claimed to vanish at φω−2ω = π/2 for all θω−2ω. However, the manuscript reports no error bars, confidence intervals, or noise floor for any of the photocurrent measurements in Fig. 2. The graphene linecuts in Fig. 2b are shown without uncertainty, and the Methods section does not describe how measurement noise was characterized. For a suppression claim to be convincing, the authors must quantify the detection limit and show that the minima at φ=π/2 are consistent with zero within experimental uncertainty, and ideally provide error bars on at least the representative linecuts (i)–(iv). Without this, the experimental demonstration of the selection rule remains unsubstantiated.
minor comments (5)
  1. [Introduction, first paragraph] The phrase 'break break time-reversal symmetry' contains a duplicated word; please correct it to 'break time-reversal symmetry'.
  2. [Methods, Eq. (2) and surrounding text] The text introducing Eq. (2) lists 'ϵ the ellipticity of the 2ω field' as a parameter, but ϵ does not appear in Eq. (2). Either remove the unused parameter or include it in the field definition if it was intended to control the 2ω polarization.
  3. [Methods, Eq. (2)] The factor of 1/2 multiplying the 2ω term, combined with the stated amplitude ratio Δ = 0.75, is not explained. Please clarify whether Δ refers to the electric-field amplitude ratio and why the explicit 1/2 factor appears; otherwise the reader cannot reproduce the simulations.
  4. [Fig. 4 caption] The word 'ab-inito' should be 'ab initio'.
  5. [Results, Fig. 2b(ii)] The text states that at φ=π/2 the field is 'clearly polarized in the two-dimensional space of the monolayer plane' and that mirror symmetry is broken for generic θ. This is true only if the 2ω components share a common time dependence; the current Eq. (2) does not yield that behavior. This point is already covered in Major Comment 1, but the figure caption and main text should be made consistent with the corrected field definition.

Circularity Check

0 steps flagged · score 0.0 of 10

No circularity found: the TRS photocurrent selection rule is derived from a parameter-free symmetry argument and benchmarked against experiment; the printed Eq. (2) inconsistency is a correctness issue, not a circular reduction.

full rationale

The derivation chain is self-contained. The central selection rule follows from a parameter-free symmetry argument: for a TRS-preserving field and a TRS-invariant material, carriers are excited equally at k and -k, so the net bulk photogalvanic current vanishes. No free parameter is fitted to photocurrent data. The graphene measurement is an external experimental benchmark on epitaxial monolayer graphene, and the TDDFT simulations use experimental field parameters (E0, wavelength, envelope, amplitude ratio), so the agreement is not enforced by construction. The CrI3 and Floquet-Chern results are forward ab initio simulations of the same code with a magnetic ground state or a circularly dressed Hamiltonian; they are consequences of the same symmetry premise but are not statistically forced by any fitted input. Self-citations (refs. [25] and [40]) provide experimental details and a Floquet symmetry classification, but the load-bearing statement E(t)=E(-t) at phi=pi/2 is asserted directly in the manuscript text rather than imported solely from those citations, so no load-bearing self-citation chain is present. One non-circular correctness concern should be flagged: Methods Eq. (2) as printed contains cos(2wt) for the x-component and sin(2wt) for the y-component of the 2w vector potential, which makes the 2w component elliptically polarized and gives E_x odd under t->-t for theta not 90 degrees at phi=pi/2, contradicting the text's assertion of linear polarization and TRS for all theta. This is an internal inconsistency or typo that the authors should correct or clarify; it does not make the predictions equivalent to their inputs by definition.

Assumptions & free parameters 2 free parameters · 5 assumptions · 0 invented entities

No new particles, forces, conserved quantities, or dimensions are introduced; the Floquet-Chern and magnetic states are known phases, not inventions. The free parameters listed are experimental inputs and pulse-shape choices, not fitted constants.

free parameters (2)
  • Two-color amplitude ratio Delta = 0.75
    Set to the ratio of measured 2-omega to omega field amplitudes (0.2/0.27 V/nm); not varied to match photocurrents, but a model input.
  • Envelope exponent sigma = 0.75
    Chosen in the super-sine pulse envelope to mimic the experimental pulse; not fitted to the photocurrent data.
assumptions (5)
  • ad hoc to paper The phi=pi/2 tailored field preserves TRS for all theta (E(t)=E(-t)).
    Asserted in Results without derivation; appears inconsistent with Eq. (2) for theta not equal to 90 degrees, so the central classification rests on this premise.
  • standard math In a TRS-invariant material, a TRS-preserving field excites equal populations at k and -k, so the injection current vanishes.
    Analytic argument in Results; a standard symmetry consequence, not circular.
  • domain assumption Monolayer graphene on SiC behaves as an isolated, inversion- and TRS-symmetric 2D system with negligible substrate symmetry breaking.
    Used implicitly in interpreting the experimental photocurrent map as an intrinsic graphene response.
  • domain assumption Adiabatic LDA TDDFT accurately describes the photocurrent dynamics in graphene, CrI3, and Floquet-dressed graphene.
    All ab initio results use aLDA in Octopus; CrI3 is a correlated magnet where aLDA is a strong approximation.
  • domain assumption The 2200 nm circular dressing field realizes a Floquet Chern insulator in graphene with a roughly 0.1 eV gap and does not itself generate photocurrent.
    Relies on refs. [65,66] and on the authors' simulations; the topological gap is an input to the probe interpretation.

how reviews work

0 comments
Cite this review

Pith. "Pith review of Probing broken time-reversal symmetry with tailored-light photocurrents." pith.science (2026). https://pith.science/paper/7MMDWRPS

@misc{pith2026250705768,
  author       = {Pith},
  title        = {Pith review of: Probing broken time-reversal symmetry with tailored-light photocurrents},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/7MMDWRPS}},
  note         = {Machine review of arXiv:2507.05768}
}
read the original abstract

Light-field-driven photocurrents represent a powerful tool for generating photocurrents without external bias in light-matter systems that lack inversion symmetry. While these photocurrents are used in electronic applications, such as current sources, switches, and photovoltaics, their presence can also be used to probe material properties in and out of equilibrium, such as topology. Here we advance this path of light-field-driven photocurrent spectroscopy by utilizing tailored laser fields for ultrafast photocurrent generation to study time-reversal symmetry (TRS) broken phases. We employ combinations of bichromatic linearly-polarized laser beams that individually respect mirror (spatial) and time-reversal symmetry, individually precluding photocurrents, but when combined can break symmetries and generate photocurrents. We show, both theoretically and experimentally, that unique choices of the relative polarization angle and two-color phase imposes a forbidden photocurrent selection rule in TRS-invariant systems, as the tailored light maintains TRS while breaking all other spatial symmetries. We then employ state-of-the-art ab-initio simulations to validate this physical mechanism, and, crucially, predict its breaking in materials with intrinsically-broken TRS, creating a background free signal for magnetism and Chern physics. Our work paves way for probing TRS-broken phases of matter in an ultrafast time-resolved manner, not requiring the application of external magnetic fields or even circularly-polarized electric fields.

Figures

Figures reproduced from arXiv: 2507.05768 by the authors.

Figure 1
Figure 1. FIG. 1 [PITH_FULL_IMAGE:figures/full_fig_p004_1.png] view at source ↗
Figure 2
Figure 2. FIG. 2 [PITH_FULL_IMAGE:figures/full_fig_p004_2.png] view at source ↗
Figure 3
Figure 3. FIG. 3 [PITH_FULL_IMAGE:figures/full_fig_p006_3.png] view at source ↗
Figures from the paper (1 more)
Figure 4
Figure 4. Figure 4: FIG. 4 [PITH_FULL_IMAGE:figures/full_fig_p008_4.png]

Discussion (0). Continue with ORCID to comment.

Reference graph

Works this paper leans on

83 extracted references · 79 canonical work pages

  1. [1]

    & Reis, D

    Ghimire, S. & Reis, D. A. High-harmonic gen- eration from solids. Nature Physics 15, 10–16 (2018)

  2. [2]

    & Brabec, T

    Goulielmakis, E. & Brabec, T. High harmonic generation in condensed matter. Nature Photonics 16, 411–421 (2022)

  3. [3]

    Heide, C., Kobayashi, Y., Haque, S. R. U. & Ghimire, S. Ultrafast high-harmonic spectroscopy of solids. Nature Physics 20, 1546–1557 (2024)

  4. [4]

    Heide, C. et al. Probing electron-hole coher- ence in strongly driven 2D materials using high- harmonic generation. Optica 9, 512 (2022)

  5. [5]

    Freudenstein, J. et al. Attosecond clocking of correlations between bloch electrons. Nature 610, 290–295 (2022)

  6. [6]

    B., Chan, Y.-h

    Chang Lee, V., Yue, L., Gaarde, M. B., Chan, Y.-h. & Qiu, D. Y. Many-body enhancement of high-harmonic generation in monolayer mos2. Nature Communications 15 (2024). 9

  7. [7]

    Molinero, E. B. et al. Subcycle dynamics of exci- tons under strong laser fields. Science Advances 10 (2024)

  8. [8]

    Jensen, S. V. B., Madsen, L. B., Rubio, A. & Tancogne-Dejean, N. High-harmonic spec- troscopy of strongly bound excitons in solids. Physical Review A 109 (2024)

Show all 83 references
  1. [9]

    Alcal` a, J. et al. High-harmonic spec- troscopy of quantum phase transi- tions in a high-tc superconductor. Proceedings of the National Academy of Sciences 119 (2022)

  2. [10]

    Bionta, M. R. et al. Tracking ultrafast solid-state dynamics using high harmonic spec- troscopy. Physical Review Research 3 (2021)

  3. [11]

    Uchida, K. et al. High-order harmonic generation and its unconventional scal- ing law in the mott-insulating Ca 2RuO4. Physical Review Letters 128 (2022)

  4. [12]

    Bai, Y. et al. High-harmonic generation from topological surface states. Nature Physics 17, 311–315 (2020)

  5. [13]

    Schmid, C. P. et al. Tunable non-integer high- harmonic generation in a topological insulator. Nature 593, 385–390 (2021)

  6. [14]

    Lv, Y.-Y. et al. High-harmonic gen- eration in weyl semimetal β-wp2 crystals. Nature Communications 12 (2021)

  7. [15]

    Heide, C. et al. Probing topological phase transitions using high-harmonic generation. Nature Photonics 16, 620–624 (2022)

  8. [16]

    & Rubio, A

    Neufeld, O., Tancogne-Dejean, N., H¨ ubener, H., De Giovannini, U. & Rubio, A. Are there universal signatures of topological phases in high-harmonic generation? probably not. Physical Review X 13 (2023)

  9. [17]

    Uzan-Narovlansky, A. J. et al. Observation of interband berry phase in laser-driven crystals. Nature 626, 66–71 (2024)

  10. [18]

    & Rubio, A

    Neufeld, O., Zhang, J., De Giovannini, U., H¨ ubener, H. & Rubio, A. Probing phonon dynamics with multidimensional high har- monic carrier-envelope-phase spectroscopy. Proceedings of the National Academy of Sciences 119 (2022)

  11. [19]

    Zhang, J. et al. High-harmonic spectroscopy probes lattice dynamics. Nature Photonics 18, 792–798 (2024)

  12. [20]

    Ma, Q., Krishna Kumar, R., Xu, S.-Y., Kop- pens, F. H. L. & Song, J. C. W. Photocurrent as a multiphysics diagnostic of quantum materi- als. Nature Reviews Physics 5, 170–184 (2023)

  13. [21]

    Pettine, J. et al. Ultrafast terahertz emis- sion from emerging symmetry-broken materials. Light: Science and; Applications 12 (2023)

  14. [22]

    H., Refael, G

    Chan, C.-K., Lindner, N. H., Refael, G. & Lee, P. A. Photocurrents in weyl semimetals. Physical Review B 95 (2017)

  15. [23]

    G., Morimoto, T

    de Juan, F., Grushin, A. G., Morimoto, T. & Moore, J. E. Quantized circu- lar photogalvanic effect in weyl semimetals. Nature Communications 8 (2017)

  16. [24]

    McIver, J. W. et al. Light-induced anoma- lous hall effect in graphene. Nature Physics 16, 38–41 (2019)

  17. [25]

    Lesko, D. M. B. et al. Optical control of elec- trons in a floquet topological insulator (2025). 2407.17917

  18. [26]

    Ju, L. et al. Tunable excitons in bilayer graphene. Science 358, 907–910 (2017)

  19. [27]

    Orenstein, J. et al. Topology and symmetry of quantum materi- als via nonlinear optical responses. Annual Review of Condensed Matter Physics 12, 247–272 (2021)

  20. [28]

    Han, T. et al. Accurate measurement of the gap of Graphene-hBN Moir´ e su- perlattice through photocurrent spectroscopy. Physical Review Letters 126 (2021)

  21. [29]

    Yang, J. et al. Spectroscopy signatures of electron correlations in a trilayer graphene/hbn moir´ e superlattice. Science 375, 1295–1299 (2022)

  22. [30]

    R., Neufeld, O

    Habibovi´ c, D., Hamilton, K. R., Neufeld, O. & Rego, L. Emerging tailored light sources for studying chirality and symmetry. Nature Reviews Physics 6, 663–675 (2024)

  23. [31]

    & Kobayashi, Y

    Watanabe, S., Kondo, K., Nabekawa, Y., Sag- isaka, A. & Kobayashi, Y. Two-color phase con- trol in tunneling ionization and harmonic gen- eration by a strong laser field and its third har- monic. Physical Review Letters 73, 2692–2695 (1994)

  24. [32]

    Eichmann, H. et al. Polarization-dependent high-order two-color mixing. Physical Review A 51, R3414–R3417 (1995)

  25. [33]

    D., Cormier, E

    Andiel, U., Tsakiris, G. D., Cormier, E. & Witte, K. High-order harmonic amplitude mod- ulation in two-colour phase-controlled frequency mixing. Europhysics Letters (EPL) 47, 42–48 (1999)

  26. [34]

    Dudovich, N. et al. Measuring and con- trolling the birth of attosecond xuv pulses. Nature Physics 2, 781–786 (2006)

  27. [35]

    & Cohen, O

    Fleischer, A., Kfir, O., Diskin, T., Sidorenko, P. & Cohen, O. Spin angular momentum and tun- able polarization in high-harmonic generation. Nature Photonics 8, 543–549 (2014)

  28. [36]

    Hickstein, D. D. et al. Non-collinear genera- tion of angularly isolated circularly polarized 10 high harmonics. Nature Photonics 9, 743–750 (2015)

  29. [37]

    V., Arribi, P

    Trevisan, T. V., Arribi, P. V., Heinonen, O., Slager, R.-J. & Orth, P. P. Bicircular light floquet engineering of magnetic symmetry and topology and its application to the dirac semimetal Cd 3As2. Physical Review Letters 128 (2022)

  30. [38]

    & Viebahn, K

    Wang, Y., Walter, A.-S., Jotzu, G. & Viebahn, K. Topological floquet engineering using two fre- quencies in two dimensions. Physical Review A 107 (2023)

  31. [39]

    & Esslinger, T

    Zhu, Z., G¨ achter, M., Walter, A.-S., Viebahn, K. & Esslinger, T. Reversal of quantized hall drifts at noninteracting and interacting topolog- ical boundaries. Science 384, 317–320 (2024)

  32. [40]

    Degree of time-reversal and dy- namical symmetry breaking in electromagnetic fields and its connection to floquet engineering

    Neufeld, O. Degree of time-reversal and dy- namical symmetry breaking in electromagnetic fields and its connection to floquet engineering. ACS Photonics 12, 2151–2159 (2025)

  33. [41]

    Uzan-Narovlansky, A. J. et al. Observation of light-driven band structure via multiband high- harmonic spectroscopy. Nature Photonics 16, 428–432 (2022)

  34. [42]

    Mitra, S. et al. Light-wave-controlled haldane model in monolayer hexagonal boron nitride. Nature 628, 752–757 (2024)

  35. [43]

    Tyulnev, I. et al. Valleytronics in bulk mos2 with a topologic optical field. Nature 628, 746–751 (2024)

  36. [44]

    Atanasov, R., Hach´ e, A., Hughes, J. L. P., van Driel, H. M. & Sipe, J. E. Coherent control of photocurrent generation in bulk semiconduc- tors. Physical Review Letters 76, 1703–1706 (1996)

  37. [45]

    Hach´ e, A. et al. Observation of coherently controlled photocurrent in unbiased, bulk gaas. Physical Review Letters 78, 306–309 (1997)

  38. [46]

    Sun, D. et al. Coherent control of ballistic photocurrents in multilayer epitaxial graphene using quantum interference. Nano Letters 10, 1293–1296 (2010)

  39. [47]

    & Sipe, J

    Rioux, J., Burkard, G. & Sipe, J. E. Cur- rent injection by coherent one- and two- photon excitation in graphene and its bilayer. Physical Review B 83 (2011)

  40. [48]

    Sternemann, E. et al. Femtosecond quantum in- terference control of electrical currents in gaas: Signatures beyond the perturbative χ3 limit. Physical Review B 88 (2013)

  41. [49]

    Sederberg, S. et al. Vectorized optoelectronic control and metrology in a semiconductor. Nature Photonics 14, 680–685 (2020)

  42. [50]

    & Dixit, G

    Bharti, A. & Dixit, G. Photocurrent gen- eration in solids via linearly polarized laser. Physical Review B 109 (2024)

  43. [51]

    Jim´ enez-Gal´ an,´A., Silva, R. E. F., Smirnova, O. & Ivanov, M. Lightwave control of topo- logical properties in 2D materials for sub- cycle and non-resonant valley manipulation. Nature Photonics 14, 728–732 (2020)

  44. [52]

    S., Jim´ enez-Gal´ an,´A., Ivanov, M

    Mrudul, M. S., Jim´ enez-Gal´ an,´A., Ivanov, M. & Dixit, G. Light-induced valleytronics in pristine graphene. Optica 8, 422–427 (2021)

  45. [53]

    & Bandrauk, A

    Yuan, K.-J. & Bandrauk, A. D. Attosecond- magnetic-field-pulse generation by electronic currents in bichromatic circularly polarized uv laser fields. Physical Review A 92 (2015)

  46. [54]

    & Corkum, P

    Sederberg, S., Kong, F. & Corkum, P. B. Tesla-scale terahertz magnetic impulses. Physical Review X 10 (2020)

  47. [55]

    & M¨ unzenberg, M

    Walowski, J. & M¨ unzenberg, M. Perspec- tive: Ultrafast magnetism and thz spintronics. Journal of Applied Physics 120 (2016)

  48. [56]

    Siegrist, F. et al. Light-wave dynamic control of magnetism. Nature 571, 240–244 (2019)

  49. [57]

    & Rubio, A

    Neufeld, O., Tancogne-Dejean, N., De Giovan- nini, U., H¨ ubener, H. & Rubio, A. Attosec- ond magnetization dynamics in non-magnetic materials driven by intense femtosecond lasers. npj Computational Materials 9 (2023)

  50. [58]

    F., He, K., Shan, J

    Mak, K. F., He, K., Shan, J. & Heinz, T. F. Control of valley polarization in monolayer mos2 by optical helicity. Nature Nanotechnology 7, 494–498 (2012)

  51. [59]

    Yang, L. et al. Long-lived nanosecond spin relaxation and spin coherence of electrons in monolayer mos2 and ws2. Nature Physics 11, 830–834 (2015)

  52. [60]

    Herrmann, P. et al. Nonlinear valley se- lection rules and all-optical probe of broken time-reversal symmetry in monolayer WSe 2. Nature Photonics 19, 300–306 (2025)

  53. [61]

    & Gedik, N

    Wang, Y. & Gedik, N. Circular dichro- ism in angle-resolved photoemission spectroscopy of topological insulators. physica status solidi (RRL) – Rapid Research Letters 7, 64–71 (2013)

  54. [62]

    & Damascelli, A

    Boschini, F., Zonno, M. & Damascelli, A. Time- resolved arpes studies of quantum materials. Reviews of Modern Physics 96 (2024)

  55. [63]

    Heinrich, T. et al. Chiral high-harmonic generation and spectroscopy on solid sur- faces using polarization-tailored strong fields. Nature Communications 12 (2021)

  56. [64]

    Huang, B. et al. Layer-dependent ferromag- netism in a van der waals crystal down to the monolayer limit. Nature 546, 270–273 (2017). 11

  57. [65]

    & Aoki, H

    Oka, T. & Aoki, H. Photovoltaic hall effect in graphene. Physical Review B 79 (2009)

  58. [66]

    H., Refael, G

    Lindner, N. H., Refael, G. & Galitski, V. Floquet topological insulator in semiconduc- tor quantum wells. Nature Physics 7, 490–495 (2011)

  59. [67]

    & Cerullo, G

    Brida, D., Manzoni, C. & Cerullo, G. Phase- locked pulses for two-dimensional spectroscopy by a birefringent delay line. Optics Letters 37, 3027 (2012)

  60. [68]

    & Cohen, O

    Neufeld, O., Podolsky, D. & Cohen, O. Floquet group theory and its application to selection rules in harmonic generation. Nature Communications 10 (2019)

  61. [69]

    & Albrecht, A

    Fischer, P., Beckwitt, K., Wise, F. & Albrecht, A. The chiral specificity of sum-frequency gen- eration in solutions. Chemical Physics Letters 352, 463–468 (2002)

  62. [70]

    Ayuso, D. et al. Synthetic chiral light for effi- cient control of chiral light–matter interaction. Nature Photonics 13, 866–871 (2019)

  63. [71]

    Neufeld, O. et al. Ultrasensitive chiral spec- troscopy by dynamical symmetry breaking in high harmonic generation. Physical Review X 9 (2019)

  64. [72]

    Mayer, N. et al. Chiral topological light for de- tection of robust enantiosensitive observables. Nature Photonics 18, 1155–1160 (2024)

  65. [73]

    & Rubio, A

    Neufeld, O., Tancogne-Dejean, N., De Giovan- nini, U., H¨ ubener, H. & Rubio, A. Light- driven extremely nonlinear bulk photogalvanic currents. Physical Review Letters 127 (2021)

  66. [74]

    Liu, Y. et al. Signatures of floquet electronic steady states in graphene un- der continuous-wave mid-infrared irradiation. Nature Communications 16 (2025)

  67. [75]

    Nova, T. F. et al. An effective magnetic field from optically driven phonons. Nature Physics 13, 132–136 (2016)

  68. [76]

    Luo, J. et al. Large effective magnetic fields from chiral phonons in rare-earth halides. Science 382, 698–702 (2023)

  69. [77]

    Song, C. et al. Altermagnets as a new class of functional materials. Nature Reviews Materials (2025)

  70. [78]

    P., Paltiel, Y., Naaman, R

    Bloom, B. P., Paltiel, Y., Naaman, R. & Waldeck, D. H. Chiral induced spin selectivity. Chemical Reviews 124, 1950–1991 (2024)

  71. [79]

    Evers, F. et al. Theory of chirality in- duced spin selectivity: Progress and challenges. Advanced Materials 34, 2106629 (2022)

  72. [80]

    Lesko, D. M. B. et al. A six-octave optical fre- quency comb from a scalable few-cycle erbium fi- bre laser. Nature Photonics 15, 281–286 (2021)

  73. [81]

    Tancogne-Dejean, N. et al. Octopus, a computational framework for exploring light-driven phenomena and quantum dy- namics in extended and finite systems. The Journal of Chemical Physics 152 (2020)

  74. [82]

    & Hutter, J

    Hartwigsen, C., Goedecker, S. & Hutter, J. Relativistic separable dual-space gaussian pseu- dopotentials from h to rn. Physical Review B 58, 3641–3662 (1998)

  75. [83]

    & Cohen, O

    Neufeld, O. & Cohen, O. Background- free measurement of ring currents by symmetry-breaking high-harmonic spec- troscopy. Physical Review Letters 123 (2019). Acknowledgments: The authors thank Dr. Lu Wang for her comments on the manuscript. ON acknowledges the scientific suppor...

Pith tools

Reviewed August 6, 2026 · model on record in the stance chip above.