Quantum Materials Link Light and Magnetism in Atomically Thin Layers

A new review highlights advancements in atomically thin quantum materials where light and magnetism interact. These materials are only a few atoms thick. This interaction creates new possibilities for controlling magnetic states using light.

Researchers at the City College of New York are studying these materials. Their work focuses on systems where light, electric charge, and magnetism are closely connected. These interactions could lead to advanced optoelectronic devices and quantum technologies.

The review, published in *Nature Materials*, details progress in layered magnetic semiconductors. In these materials, light-generated excitations, called excitons, interact with magnetic order and magnetic waves known as magnons. An exciton forms when light energizes an electron, leaving a positively charged hole. Magnons are collective waves traveling through a material's magnetic structure.

Unlike previous methods, van der Waals magnetic semiconductors allow excitons and magnetic moments to originate from the same electronic orbitals. This shared origin enables light and magnetism to influence each other directly within the material. Excitons can strengthen magneto-optical effects, allowing scientists to identify magnetic states by observing changes in light polarization. Magnetic order can also alter exciton energy and confinement.

Potential applications include magneto-photonic memory, all-optical logic, and adjustable light-emitting devices. Quantum transducers, which convert signals between microwave and optical frequencies, are another promising area. These could connect components in future quantum networks.

Despite rapid progress, much remains unknown. Many materials are unexplored, and scientists need better theoretical models. Future research will investigate moiré magnetic excitons and optical control of spin textures.