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arxiv: 2605.07190 · v1 · submitted 2026-05-08 · ❄️ cond-mat.mes-hall

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· Lean Theorem

Floquet second-order topological insulator in strained graphene

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Pith reviewed 2026-05-11 02:29 UTC · model grok-4.3

classification ❄️ cond-mat.mes-hall
keywords floquet engineeringsecond-order topological insulatorstrained graphenehigher-order topologylight-driven phasescorner modesdirac conespolarization invariant
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The pith

Uniaxial strain and off-resonant circular light create a Floquet second-order topological insulator in graphene with protected corner modes.

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 graphene, combined with off-resonant circularly polarized light at a tunable oblique angle, drives the system into a phase where the edges of a finite sample are gapped but zero-dimensional corner modes remain robustly localized. Strain pushes the Dirac cones toward a semi-Dirac merging point, making the light-induced gap strongly anisotropic; the resulting effective Hamiltonian then carries a vanishing Chern number yet a nonzero crystalline-symmetry-quantized polarization that enforces the corner states. The authors obtain this effective description via a high-frequency expansion of the driven strained tight-binding model with Peierls coupling and confirm the topology with both analytic invariants and first-principles-informed calculations on nanostructures. A sympathetic reader would care because the combination offers a simple, experimentally accessible platform for higher-order Floquet topology without requiring artificial lattices or complex band engineering.

Core claim

In a strained honeycomb tight-binding model with Peierls substitution for the vector potential, off-resonant circular drive at oblique incidence projects to an elliptically polarized field whose anisotropic mass term, when combined with uniaxial strain, opens a gap while preserving a quantized polarization invariant; this invariant guarantees in-gap corner modes in finite geometries even though the bulk Chern number is zero, thereby realizing a Floquet second-order topological insulator whose phase boundary is controlled by strain magnitude and incidence angle.

What carries the argument

The high-frequency effective Floquet Hamiltonian that incorporates uniaxial strain and the elliptically polarized component from oblique incidence, which produces an anisotropic Dirac mass and stabilizes a crystalline-symmetry-quantized polarization.

If this is right

  • The phase can be entered and exited by continuously varying either the strain strength or the light incidence angle, producing a tunable phase diagram.
  • The corner modes are protected by the polarization invariant and therefore survive smooth deformations that preserve the relevant crystalline symmetries.
  • First-principles tight-binding calculations on realistic nanostructures reproduce the same topological evolution, indicating the effect should be observable in fabricated samples.
  • The bulk remains topologically trivial by the Chern number yet hosts higher-order boundary states, separating this phase from conventional Floquet Chern insulators.

Where Pith is reading between the lines

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

  • The same strain-plus-oblique-drive protocol could be applied to other Dirac materials such as transition-metal dichalcogenides to generate analogous corner modes.
  • Time-resolved local probes could map the corner-state wavefunctions and their dependence on drive parameters in real devices.
  • Because the drive is off-resonant, heating effects are expected to be weaker than in resonant Floquet schemes, potentially extending the lifetime of the corner states.
  • Engineering the strain direction relative to the light polarization axis offers an extra control knob for switching between first-order and second-order topological regimes.

Load-bearing premise

The high-frequency expansion remains accurate for the chosen drive frequency and the strained tight-binding model with Peierls coupling fully captures the light-matter interaction without higher-order corrections.

What would settle it

In a finite strained graphene flake illuminated by off-resonant circularly polarized light at oblique incidence, the appearance of robust in-gap states localized at the corners while the edges stay fully gapped would confirm the predicted second-order phase.

Figures

Figures reproduced from arXiv: 2605.07190 by Dong-Hui Xu, Rui Wang, Xiaolin Wan, Yu-Wen Xu, Zi-Ming Wang.

Figure 1
Figure 1. Figure 1: FIG. 1. Uniaxial strain and driven-graphene geometry. (a) Uniaxi [PITH_FULL_IMAGE:figures/full_fig_p002_1.png] view at source ↗
Figure 3
Figure 3. Figure 3: FIG. 3. Semi-Dirac regime and Floquet second-order topology. (a) [PITH_FULL_IMAGE:figures/full_fig_p003_3.png] view at source ↗
Figure 4
Figure 4. Figure 4: FIG. 4. First-principles-informed realization in strained graphene. (a) [PITH_FULL_IMAGE:figures/full_fig_p004_4.png] view at source ↗
read the original abstract

Graphene provides a canonical setting for Floquet band engineering, where circularly polarized light can dynamically open topological gaps at Dirac points and generate nonequilibrium Hall responses. Here we show that uniaxial strain and off-resonant circularly polarized light with tunable incidence angle enable a controllable route to Floquet higher-order topology in graphene. Using a strained honeycomb tight-binding model with Peierls coupling and a high-frequency expansion for the effective Floquet Hamiltonian, we find that strain drives the Dirac cones toward the Dirac-merging (semi-Dirac) critical regime, where the light-induced mass becomes strongly anisotropic. For oblique incidence, the projected drive is effectively elliptically polarized and, in combination with strain, stabilizes a phase with gapped edges but robust in-gap corner modes in finite geometries, realizing a Floquet second-order topological insulator. We characterize the phase diagram via the Chern number and a crystalline-symmetry-quantized polarization invariant. Finally, first-principles-informed tight-binding calculations corroborate the predicted topological evolution in strained graphene nanostructures. Our results identify driven strained graphene as a realistic and tunable platform for realizing and diagnosing Floquet higher-order topological phases.

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

1 major / 2 minor

Summary. The manuscript claims that uniaxial strain combined with off-resonant circularly polarized light at tunable incidence angles provides a controllable route to a Floquet second-order topological insulator in graphene. A strained honeycomb tight-binding model with Peierls coupling is used together with a high-frequency expansion to obtain an effective Floquet Hamiltonian; strain tunes the Dirac cones toward a semi-Dirac regime where the light-induced mass is strongly anisotropic. For oblique incidence the projected drive is elliptically polarized, stabilizing a phase with gapped edges but robust corner modes in finite geometries. The phase is characterized by the Chern number and a crystalline-symmetry-quantized polarization, with supporting first-principles-informed tight-binding calculations.

Significance. If substantiated, the result supplies a realistic, experimentally tunable platform for Floquet higher-order topology by combining two accessible control knobs (strain and incidence angle) in a well-characterized material. The use of standard tight-binding plus Magnus expansion methods, together with first-principles checks, makes the proposal concrete and potentially testable in graphene nanostructures.

major comments (1)
  1. [section describing the high-frequency expansion and effective Hamiltonian] The high-frequency expansion for the effective Floquet Hamiltonian is applied in the strain-tuned regime approaching the semi-Dirac point, where one Dirac velocity vanishes and the local bandwidth shrinks. In this limit the expansion parameter (drive frequency versus renormalized hopping) is no longer uniformly large, so omitted higher-order Magnus terms or residual resonant processes could modify the anisotropy of the induced mass and thereby change the computed Chern number or polarization invariant. Explicit bounds on the expansion error or direct comparison with exact Floquet diagonalization for representative parameter values is required to confirm that the reported topological phase survives.
minor comments (2)
  1. [figures and captions] Figure captions and the phase-diagram presentation would benefit from explicit listing of the numerical values of strain strength and incidence angle used for each panel.
  2. [model section] Notation for the projected electric-field components under oblique incidence should be introduced once and used consistently in both the text and the supplementary material.

Simulated Author's Rebuttal

1 responses · 0 unresolved

We thank the referee for the positive overall assessment and for the detailed major comment, which raises a substantive point about the applicability of our high-frequency expansion. We address this concern directly below and will incorporate additional validation into the revised manuscript.

read point-by-point responses
  1. Referee: The high-frequency expansion for the effective Floquet Hamiltonian is applied in the strain-tuned regime approaching the semi-Dirac point, where one Dirac velocity vanishes and the local bandwidth shrinks. In this limit the expansion parameter (drive frequency versus renormalized hopping) is no longer uniformly large, so omitted higher-order Magnus terms or residual resonant processes could modify the anisotropy of the induced mass and thereby change the computed Chern number or polarization invariant. Explicit bounds on the expansion error or direct comparison with exact Floquet diagonalization for representative parameter values is required to confirm that the reported topological phase survives.

    Authors: We agree that the high-frequency (Magnus) expansion requires careful scrutiny near the semi-Dirac point, where the renormalized bandwidth is reduced. In the revised manuscript we will add explicit estimates of the magnitude of the next-order terms in the expansion for the strain and drive parameters used in our phase diagrams. We will also include direct comparisons of the effective Hamiltonian with exact Floquet diagonalization (via numerical time-evolution over one period) for representative points, including those approaching the semi-Dirac regime. These checks will confirm that the anisotropy of the light-induced mass, the Chern number, and the crystalline-symmetry-quantized polarization remain unchanged within the reported phase, thereby validating the topological characterization. revision: yes

Circularity Check

0 steps flagged

No significant circularity; derivation uses standard Floquet and topological invariants

full rationale

The paper constructs the effective Hamiltonian via the standard high-frequency Magnus expansion applied to a strained tight-binding model with Peierls substitution, then diagnoses the phase using the conventional Chern number and crystalline-symmetry-quantized polarization. These steps rely on established techniques without reducing any central claim (e.g., the existence of corner modes) to a fitted parameter or self-referential definition. No load-bearing self-citation chains or ansatz smuggling appear in the derivation; the first-principles corroboration is external validation rather than internal closure. The skeptic concern about expansion validity near the semi-Dirac point is a question of approximation accuracy, not circularity of the logical chain.

Axiom & Free-Parameter Ledger

2 free parameters · 2 axioms · 0 invented entities

The central claim rests on standard condensed-matter approximations and models rather than new postulates or heavily fitted parameters.

free parameters (2)
  • uniaxial strain strength
    Parameter that drives Dirac cones to the semi-Dirac regime; treated as experimentally tunable rather than fitted to the target topology.
  • light incidence angle
    Tunable experimental knob that controls the effective ellipticity of the drive.
axioms (2)
  • domain assumption High-frequency expansion yields a reliable effective Floquet Hamiltonian for off-resonant driving
    Invoked to obtain the time-averaged Hamiltonian from the time-periodic drive.
  • domain assumption Tight-binding model with Peierls substitution captures light-matter coupling in strained graphene
    Standard modeling choice for the honeycomb lattice under strain and electromagnetic drive.

pith-pipeline@v0.9.0 · 5505 in / 1462 out tokens · 83467 ms · 2026-05-11T02:29:09.969339+00:00 · methodology

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Works this paper leans on

100 extracted references · 100 canonical work pages · 1 internal anchor

  1. [1]

    and quantum spin Hall (QSH) [4] effects. In these models, the transition to a topological phase is achieved by generat- ing a Dirac mass term (staggered flux or intrinsic spin–orbit coupling), highlighting how symmetry constrains permissi- ble masses and thereby dictates band topology and quantized boundary responses. A particularly powerful extension of ...

  2. [2]

    Vafek and A

    O. Vafek and A. Vishwanath, Dirac fermions in solids: From high-Tc cuprates and graphene to topological insulators and Weyl semimetals, Annu. Rev. Condens. Matter Phys.5, 83 (2014)

  3. [3]

    A. H. Castro Neto, F. Guinea, N. M. R. Peres, K. S. Novoselov, and A. K. Geim, The electronic properties of graphene, Rev. Mod. Phys.81, 109 (2009)

  4. [4]

    parity anomaly

    F. D. M. Haldane, Model for a quantum Hall effect without Landau levels: Condensed-matter realization of the “parity anomaly”, Phys. Rev. Lett.61, 2015 (1988)

  5. [5]

    C. L. Kane and E. J. Mele, Quantum spin hall effect in graphene, Phys. Rev. Lett.95, 226801 (2005)

  6. [6]

    Cayssol, B

    J. Cayssol, B. D ´ora, F. Simon, and R. Moessner, Floquet topo- logical insulators, Phys. Status Solidi RRL7, 101 (2013)

  7. [7]

    Oka and S

    T. Oka and S. Kitamura, Floquet engineering of quantum mate- rials, Annu. Rev. Condens. Matter Phys.10, 387 (2019)

  8. [8]

    Harper, R

    F. Harper, R. Roy, M. S. Rudner, and S. Sondhi, Topology and broken symmetry in Floquet systems, Annu. Rev. Condens. Mat- ter Phys.11, 345 (2020)

  9. [9]

    M. S. Rudner and N. H. Lindner, Band structure engineering and non-equilibrium dynamics in Floquet topological insula- tors, Nat. Rev. Phys.2, 229 (2020)

  10. [10]

    C. Bao, P. Tang, D. Sun, and S. Zhou, Light-induced emergent phenomena in 2D materials and topological materials, Nat. Rev. Phys.4, 33 (2022)

  11. [11]

    Oka and H

    T. Oka and H. Aoki, Photovoltaic Hall effect in graphene, Phys. Rev. B79, 081406 (2009). 6

  12. [12]

    Inoue and A

    J.-i. Inoue and A. Tanaka, Photoinduced transition between con- ventional and topological insulators in two-dimensional elec- tronic systems, Phys. Rev. Lett.105, 017401 (2010)

  13. [13]

    Kitagawa, E

    T. Kitagawa, E. Berg, M. Rudner, and E. Demler, Topological characterization of periodically driven quantum systems, Phys. Rev. B82, 235114 (2010)

  14. [14]

    Z. Gu, H. A. Fertig, D. P. Arovas, and A. Auerbach, Floquet spectrum and transport through an irradiated graphene ribbon, Phys. Rev. Lett.107, 216601 (2011)

  15. [15]

    Kitagawa, T

    T. Kitagawa, T. Oka, A. Brataas, L. Fu, and E. Demler, Transport properties of nonequilibrium systems under the application of light: Photoinduced quantum Hall insulators without Landau levels, Phys. Rev. B84, 235108 (2011)

  16. [16]

    Delplace, A

    P. Delplace, A. G ´omez-Le´on, and G. Platero, Merging of Dirac points and Floquet topological transitions in ac-driven graphene, Phys. Rev. B88, 245422 (2013)

  17. [17]

    L. E. F. Foa Torres, P. M. Perez-Piskunow, C. A. Balseiro, and G. Usaj, Multiterminal conductance of a Floquet topological in- sulator, Phys. Rev. Lett.113, 266801 (2014)

  18. [18]

    G. Usaj, P. M. Perez-Piskunow, L. E. F. Foa Torres, and C. A. Balseiro, Irradiated graphene as a tunable Floquet topological insulator, Phys. Rev. B90, 115423 (2014)

  19. [19]

    N. H. Lindner, G. Refael, and V. Galitski, Floquet topological insulator in semiconductor quantum wells, Nat. Phys.7, 490 (2011)

  20. [20]

    Kitagawa, M

    T. Kitagawa, M. S. Rudner, E. Berg, and E. Demler, Explor- ing topological phases with quantum walks, Phys. Rev. A82, 033429 (2010)

  21. [21]

    N. H. Lindner, D. L. Bergman, G. Refael, and V. Galitski, Topo- logical Floquet spectrum in three dimensions via a two-photon resonance, Phys. Rev. B87, 235131 (2013)

  22. [22]

    Jiang, T

    L. Jiang, T. Kitagawa, J. Alicea, A. R. Akhmerov, D. Pekker, G. Refael, J. I. Cirac, E. Demler, M. D. Lukin, and P. Zoller, Ma- jorana fermions in equilibrium and in driven cold-atom quantum wires, Phys. Rev. Lett.106, 220402 (2011)

  23. [23]

    M. S. Rudner, N. H. Lindner, E. Berg, and M. Levin, Anomalous edge states and the bulk-edge correspondence for periodically driven two-dimensional systems, Phys. Rev. X3, 031005 (2013)

  24. [24]

    Ezawa, Photoinduced topological phase transition and a sin- gle Dirac-cone state in silicene, Phys

    M. Ezawa, Photoinduced topological phase transition and a sin- gle Dirac-cone state in silicene, Phys. Rev. Lett.110, 026603 (2013)

  25. [25]

    G ´omez-Le´on and G

    A. G ´omez-Le´on and G. Platero, Floquet-Bloch theory and topology in periodically driven lattices, Phys. Rev. Lett.110, 200403 (2013)

  26. [26]

    A. G. Grushin, A. G ´omez-Le´on, and T. Neupert, Floquet frac- tional Chern insulators, Phys. Rev. Lett.112, 156801 (2014)

  27. [27]

    R. Wang, B. Wang, R. Shen, L. Sheng, and D. Y. Xing, Floquet Weyl semimetal induced by off-resonant light, EPL105, 17004 (2014)

  28. [28]

    Narayan, Tunable point nodes from line-node semimetals via application of light, Phys

    A. Narayan, Tunable point nodes from line-node semimetals via application of light, Phys. Rev. B94, 041409 (2016)

  29. [29]

    Yan and Z

    Z. Yan and Z. Wang, Tunable Weyl points in periodically driven nodal line semimetals, Phys. Rev. Lett.117, 087402 (2016)

  30. [30]

    Taguchi, D.-H

    K. Taguchi, D.-H. Xu, A. Yamakage, and K. T. Law, Photo- voltaic anomalous Hall effect in line-node semimetals, Phys. Rev. B94, 155206 (2016)

  31. [31]

    Gonz ´alez and R

    J. Gonz ´alez and R. A. Molina, Macroscopic degeneracy of zero- mode rotating surface states in 3D Dirac and Weyl semimetals under radiation, Phys. Rev. Lett.116, 156803 (2016)

  32. [32]

    Narayan, Floquet dynamics in two-dimensional semi-Dirac semimetals and three-dimensional Dirac semimetals, Phys

    A. Narayan, Floquet dynamics in two-dimensional semi-Dirac semimetals and three-dimensional Dirac semimetals, Phys. Rev. B91, 205445 (2015)

  33. [33]

    Saha, Photoinduced chern insulating states in semi-Dirac ma- terials, Phys

    K. Saha, Photoinduced chern insulating states in semi-Dirac ma- terials, Phys. Rev. B94, 081103 (2016)

  34. [34]

    Chan, Y.-T

    C.-K. Chan, Y.-T. Oh, J. H. Han, and P. A. Lee, Type-II Weyl cone transitions in driven semimetals, Phys. Rev. B94, 121106 (2016)

  35. [35]

    Yan and Z

    Z. Yan and Z. Wang, Floquet multi-Weyl points in crossing- nodal-line semimetals, Phys. Rev. B96, 041206 (2017)

  36. [36]

    Zou and B.-G

    J.-Y. Zou and B.-G. Liu, Floquet Weyl fermions in three- dimensional stacked graphene systems irradiated by circularly polarized light, Phys. Rev. B93, 205435 (2016)

  37. [37]

    H ¨ubener, M

    H. H ¨ubener, M. A. Sentef, U. De Giovannini, A. F. Kemper, and A. Rubio, Creating stable Floquet–Weyl semimetals by laser- driving of 3D Dirac materials, Nat. Commun.8, 1 (2017)

  38. [38]

    R. Chen, B. Zhou, and D.-H. Xu, Floquet Weyl semimetals in light-irradiated type-II and hybrid line-node semimetals, Phys. Rev. B97, 155152 (2018)

  39. [39]

    Zhang, H

    D. Zhang, H. Wang, J. Ruan, G. Yao, and H. Zhang, Engineering topological phases in the Luttinger semimetalα-Sn, Phys. Rev. B97, 195139 (2018)

  40. [40]

    Firoz Islam and A

    S. Firoz Islam and A. A. Zyuzin, Photoinduced interfacial chi- ral modes in threefold topological semimetal, Phys. Rev. B100, 165302 (2019)

  41. [41]

    T. Deng, B. Zheng, F. Zhan, J. Fan, X. Wu, and R. Wang, Pho- toinduced Floquet mixed-Weyl semimetallic phase in a carbon allotrope, Phys. Rev. B102, 201105 (2020)

  42. [42]

    A. K. Ghosh, T. Nag, and A. Saha, Systematic generation of the cascade of anomalous dynamical first- and higher-order modes in floquet topological insulators, Phys. Rev. B105, 115418 (2022)

  43. [43]

    Nag and B

    T. Nag and B. Roy, Anomalous and normal dislocation modes in floquet topological insulators, Commun. Phys.4, 1 (2021)

  44. [44]

    Nag, R.-J

    T. Nag, R.-J. Slager, T. Higuchi, and T. Oka, Dynamical syn- chronization transition in interacting electron systems, Phys. Rev. B100, 134301 (2019)

  45. [45]

    X.-L. Du, R. Chen, R. Wang, and D.-H. Xu, Weyl nodes with higher-order topology in an optically driven nodal-line semimetal, Phys. Rev. B105, L081102 (2022)

  46. [46]

    Z.-M. Wang, R. Wang, J.-H. Sun, T.-Y. Chen, and D.-H. Xu, Floquet weyl semimetal phases in light-irradiated higher- order topological dirac semimetals, Phys. Rev. B107, L121407 (2023)

  47. [47]

    F. Zhan, R. Chen, Z. Ning, D.-S. Ma, Z. Wang, D.-H. Xu, and R. Wang, Perspective: Floquet engineering topological states from effective models towards realistic materials, Quan- tum Front.3, 21 (2024)

  48. [48]

    Ning, D.-S

    Z. Ning, D.-S. Ma, J. Zeng, D.-H. Xu, and R. Wang, Flexi- ble control of chiral superconductivity in optically driven nodal point superconductors with antiferromagnetism, Phys. Rev. Lett. 133, 246606 (2024)

  49. [49]

    T. V. Trevisan, P. V. Arribi, O. Heinonen, R.-J. Slager, and P. P. Orth, Bicircular light Floquet engineering of magnetic sym- metry and topology and its application to the Dirac semimetal Cd3As2, Phys. Rev. Lett.128, 066602 (2022)

  50. [50]

    R. W. Bomantara, L. Zhou, J. Pan, and J. Gong, Coupled-wire construction of static and Floquet second-order topological in- sulators, Phys. Rev. B99, 045441 (2019)

  51. [51]

    Rodriguez-Vega, A

    M. Rodriguez-Vega, A. Kumar, and B. Seradjeh, Higher-order Floquet topological phases with corner and bulk bound states, Phys. Rev. B100, 085138 (2019)

  52. [52]

    T. Nag, V. Juriˇci´c, and B. Roy, Out of equilibrium higher-order topological insulator: Floquet engineering and quench dynam- ics, Phys. Rev. Research1, 032045 (2019)

  53. [53]

    Seshadri, A

    R. Seshadri, A. Dutta, and D. Sen, Generating a second-order topological insulator with multiple corner states by periodic driving, Phys. Rev. B100, 115403 (2019). 7

  54. [54]

    Peng and G

    Y. Peng and G. Refael, Floquet second-order topological insu- lators from nonsymmorphic space-time symmetries, Phys. Rev. Lett.123, 016806 (2019)

  55. [55]

    H. Hu, B. Huang, E. Zhao, and W. V. Liu, Dynamical singular- ities of Floquet higher-order topological insulators, Phys. Rev. Lett.124, 057001 (2020)

  56. [56]

    A. K. Ghosh, G. C. Paul, and A. Saha, Higher order topological insulator via periodic driving, Phys. Rev. B101, 235403 (2020)

  57. [57]

    Peng, Floquet higher-order topological insulators and super- conductors with space-time symmetries, Phys

    Y. Peng, Floquet higher-order topological insulators and super- conductors with space-time symmetries, Phys. Rev. Research2, 013124 (2020)

  58. [58]

    R. W. Bomantara, Time-induced second-order topological su- perconductors, Phys. Rev. Research2, 033495 (2020)

  59. [59]

    Huang and W

    B. Huang and W. V. Liu, Floquet higher-order topological insu- lators with anomalous dynamical polarization, Phys. Rev. Lett. 124, 216601 (2020)

  60. [60]

    W. Zhu, Y. D. Chong, and J. Gong, Floquet higher-order topo- logical insulator in a periodically driven bipartite lattice, Phys. Rev. B103, L041402 (2021)

  61. [61]

    Zhang and Z.-C

    R.-X. Zhang and Z.-C. Yang, Tunable fragile topology in Flo- quet systems, Phys. Rev. B103, L121115 (2021)

  62. [62]

    T. Nag, V. Juri ˇci´c, and B. Roy, Hierarchy of higher-order Flo- quet topological phases in three dimensions, Phys. Rev. B103, 115308 (2021)

  63. [63]

    W. Zhu, Y. D. Chong, and J. Gong, Symmetry analysis of anomalous Floquet topological phases, Phys. Rev. B104, L020302 (2021)

  64. [64]

    W. Zhu, M. Umer, and J. Gong, Floquet higher-order Weyl and nexus semimetals, Phys. Rev. Research3, L032026 (2021)

  65. [65]

    W. B. Rui, S.-B. Zhang, M. M. Hirschmann, Z. Zheng, A. P. Schnyder, B. Trauzettel, and Z. D. Wang, Higher-order Weyl su- perconductors with anisotropic Weyl-point connectivity, Phys. Rev. B103, 184510 (2021)

  66. [66]

    B.-Q. Wang, H. Wu, and J.-H. An, Engineering exotic second- order topological semimetals by periodic driving, Phys. Rev. B 104, 205117 (2021)

  67. [67]

    Ghosh, K

    S. Ghosh, K. Saha, and K. Sengupta, Hinge-mode dynamics of periodically driven higher-order weyl semimetals, Phys. Rev. B 105, 224312 (2022)

  68. [68]

    P. Liu, C. Cui, L. Li, R. Li, D.-H. Xu, and Z.-M. Yu, Floquet control of topological phases and hall effects inZ 2 nodal line semimetals, Phys. Rev. B111, 235105 (2025)

  69. [69]

    X. Wan, F. Zhan, X. Ding, Z. Qin, S. Huang, D.-H. Xu, and R. Wang, Floquet higher-order weyl semimetallic phase in three- dimensional graphdiyne, Phys. Rev. B113, L041109 (2026)

  70. [70]

    Huang, F

    S. Huang, F. Zhan, X. Ding, D.-H. Xu, D.-S. Ma, and R. Wang, Controllable weyl nodes and fermi arcs from floquet engineering triple fermions, Phys. Rev. B110, L121118 (2024)

  71. [71]

    J. W. McIver, B. Schulte, F.-U. Stein, T. Matsuyama, G. Jotzu, G. Meier, and A. Cavalleri, Light-induced anomalous Hall effect in graphene, Nat. Phys.16, 38 (2020)

  72. [72]

    D. Choi, M. Mogi, U. De Giovannini, D. Azoury, B. Lv, Y. Su, H. H¨ubener, A. Rubio, and N. Gedik, Observation of floquet– bloch states in monolayer graphene, Nat. Phys.21, 1100 (2025)

  73. [73]

    Merboldt, M

    M. Merboldt, M. Sch¨uler, D. Schmitt, J. P. Bange, W. Bennecke, K. Gadge, K. Pierz, H. W. Schumacher, D. Momeni, D. Steil, S. R. Manmana, M. A. Sentef, M. Reutzel, and S. Mathias, Observation of floquet states in graphene, Nat. Phys.21, 1093 (2025)

  74. [74]

    F. Wang, X. Cai, X. Tang, J. Lu, W. Chen, T. Sheng, R. Feng, H. Zhong, H. Zhang, P. Yu, and S. Zhou, Observation of floquet- induced gap in graphene, Nature Materials 10.1038/s41563- 026-02549-y (2026)

  75. [75]

    Zhang, C

    F. Zhang, C. L. Kane, and E. J. Mele, Surface state magnetiza- tion and chiral edge states on topological insulators, Phys. Rev. Lett.110, 046404 (2013)

  76. [76]

    W. A. Benalcazar, B. A. Bernevig, and T. L. Hughes, Quantized electric multipole insulators, Science357, 61 (2017)

  77. [77]

    Langbehn, Y

    J. Langbehn, Y. Peng, L. Trifunovic, F. von Oppen, and P. W. Brouwer, Reflection-symmetric second-order topological insu- lators and superconductors, Phys. Rev. Lett.119, 246401 (2017)

  78. [78]

    Z. Song, Z. Fang, and C. Fang,(d−2)-dimensional edge states of rotation symmetry protected topological states, Phys. Rev. Lett.119, 246402 (2017)

  79. [79]

    Schindler, A

    F. Schindler, A. M. Cook, M. G. Vergniory, Z. Wang, S. S. P. Parkin, B. A. Bernevig, and T. Neupert, Higher-order topologi- cal insulators, Sci. Adv.4, eaat0346 (2018)

  80. [80]

    Chen, C.-Z

    R. Chen, C.-Z. Chen, J.-H. Gao, B. Zhou, and D.-H. Xu, Higher- order topological insulators in quasicrystals, Phys. Rev. Lett. 124, 036803 (2020)

Showing first 80 references.