Researchers from ICFO, NTU Singapore, and other universities collaborated to find how electric flow in bilayer graphene can be controlled by light. The research showing how light derails electrons through graphene was published in Science. The results of this research can help scientists develop better equipment used for detection and imaging applications.
The electronic property of a material determines the flow of electrons in that material. It is usually thought that electrons flow in a straight path, but in reality, electrons can even bend according to the magnetic field. The transverse signals which are caused due to electronic flow is called “Hall” responses.
In materials such as bilayer graphene, a type of quantum material, an electron’s wave pattern can exhibit complex winding, which is referred to as quantum geometry. “Electrons are not just particles, but can have a quantum wave-like nature,” Said Justin Song, Lead author of the research.
The researchers in this study show a method to bend electrons without applying magnetic fields, the report says that by applying circular polarized light on the bilayer graphene devices, selective excitation of material is possible which can induce bent electronic flows in the material.
” We now engineered the device and setup in such a way that current only flows with light illumination. With this, we were able to avoid the background noise that hampers measurements and achieve sensitivity in the detection several orders of magnitude better than any other 2D material.” Said Dr. Koppens, Professor at ICFO, Barcelona. “Such discovery could have major implications in applications for infrared and terahertz sensing since bilayer graphene can be transformed from semimetal to semiconductor with a very small bandgap, so it can detect photons of very small energies. It may be also useful, for example, for imaging in space, medical imaging, e.g. for tissue skin cancer, or even for security applications such as the quality inspection of materials”.