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Circular Light Opens Graphene's Haldane Gap
Time-resolved photoemission directly observed a Dirac gap that appeared with circularly polarized driving and vanished with the optical field.
Summary
Time-resolved photoemission directly observed a Dirac gap that appeared with circularly polarized driving and vanished with the optical field.
Circularly polarized light has long been predicted to break time-reversal symmetry in graphene and open a topological gap at the Dirac point. The reported time- and angle-resolved photoemission experiment observes that gap directly in monolayer graphene: it appears with the optical field and only under circular polarization. Paired with Floquet theory, the authors identify the feature with a light-induced Haldane mass and infer the associated Berry curvature and Chern topology. The experiment establishes an ultrafast route to dynamically altering symmetry and topology in the tested material and conditions; it does not yet amount to a general-purpose topological device.
Why it matters
Time-resolved photoemission directly observed a Dirac gap that appeared with circularly polarized driving and vanished with the optical field.
Limits and context
- The reported time- and angle-resolved photoemission experiment observes that gap directly in monolayer graphene: it appears with the optical field and only under circular polarization.
- The experiment establishes an ultrafast route to dynamically altering symmetry and topology in the tested material and conditions; it does not yet amount to a general-purpose topological device.
Key claims
Time-resolved photoemission directly observed a Dirac gap that appeared with circularly polarized driving and vanished with the optical field.
Qualification: The reported time- and angle-resolved photoemission experiment observes that gap directly in monolayer graphene: it appears with the optical field and only under circular polarization.
Evidence: source-2026-11-02-012
Sources
- arXiv preprint 2610.42115, original v1arXiv · primary research
Corrections
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