With a flash of light, scientists have been able to control graphene’s electrons, confirming a long-suspected effect in quantum materials. A new study, headed by the in collaboration with colleagues from Braunschweig and Bremen in Germany, and Fribourg in Switzerland, and published in Nature Physics, expands graphene’s potential to unprecedented heights.
Researchers at the University of Göttingen have directly observed “Floquet states” in graphene for the first time. Their findings, published in Nature Physics, could lay the groundwork for a new generation of optically controlled materials.
Graphene is already known for its exceptional properties: strong, flexible, highly conductive, and just one atom thick. These traits have made it a favorite in advanced electronics, sensors, batteries, and more.
Now, scientists have demonstrated that graphene’s electronic behavior can be manipulated using light pulses, a Floquet engineering technique. It was previously unclear whether this engineering approach would work in semi-metallic materials like graphene.
The breakthrough ends a years-long debate.
Our measurements clearly prove that ‘Floquet effects’ occur in the photoemission spectrum of graphene. This makes it clear that Floquet engineering actually works in these systems – and the potential of this discovery is huge.
Dr. Marco Merboldt, Study First Author and Physicist, University of Göttingen
The team used femtosecond momentum microscopy to capture the fleeting effect. The method involves hitting the material with ultra-short light pulses and observing its response with another, slightly delayed pulse. This allowed the researchers to track rapid changes in the material’s electronic structure with extreme precision.
According to the researchers, the ability to control electrons this way could enable new types of devices, including components for quantum computers and high-performance sensors.
Our results open up new ways of controlling electronic states in quantum materials with light. This could lead to technologies in which electrons are manipulated in a targeted and controlled manner.
Marcel Reutzel, Professor, University of Göttingen
Professor Reutzel added that the findings may also help explore so-called topological properties, features of certain materials that remain stable even when disturbed. These properties are seen as essential to the development of robust quantum technologies.
Journal Reference:
Merboldt, M., et al. (2025) Observation of Floquet states in graphene. Nature Physics. doi.org/10.1038/s41567-025-02889-7