09 Sep. Future electronics tailored by light
Graphene is only one atom thick, but extremely conductive and stable. It is therefore used in many areas, such as flexible displays, highly sensitive sensors, powerful batteries, and efficient solar cells. A new study now takes its potential to a new level: For the first time, researchers at the University of Göttingen, together with colleagues from Braunschweig, Bremen, and Switzerland, have directly observed how so-called Floquet effects arise in graphene. This confirms what, according to the researchers, had previously been controversial: Floquet engineering—a method in which the properties of a material are specifically altered by light pulses—also works in metallic and semimetallic quantum materials such as graphene.
Detection with a femtosecond laser
The researchers used femtosecond pulse microscopy to experimentally investigate Floquet states in graphene. In this process, the samples are first excited with rapid flashes of light and then examined with a delayed light pulse in order to track dynamic processes in the material. “Our measurements clearly prove that so-called Floquet sidebands occur in the photoemission spectrum of graphene,” explains Dr. Marco Merboldt, physicist at the University of Göttingen. “This makes it clear,” says Merboldt, „that Floquet engineering actually works in these systems – and the potential is huge. This brings research closer to the goal of specifically influencing quantum materials with defined properties – and doing so with laser pulses in an extremely short time.
Customized materials
Customizing materials in this way for specific applications could form the basis for the electronics, computer technology, and sensor technology of the future. Professor Marcel Reutzel, who led the research in Göttingen together with Professor Stefan Mathias, says: „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.“ Reutzel adds: ”What is particularly exciting is that this also allows us to investigate topological properties. These are special, very stable properties that could be important for robust quantum computers or new sensors.“
Source: www.uni-goettingen.de
Image: Artistic representation of Floquet painted by physicist and artist Lina Segerer. linasegerer.de