Quantum breakthrough links light and magnetism in atomically thin materials

Researchers at the City College of New York (CCNY) are developing quantum technologies using van der Waals magnetic semiconductors, materials only a few atoms thick where light, electric charge, and magnetism interact directly. According to a review published in Nature Materials, these materials allow light-generated excitations called excitons to sense and control magnetic states, potentially enabling new forms of all-optical logic and quantum transducers.

How Van der Waals Magnetic Semiconductors Merge Light and Magnetism

For years, scientists tried to combine the optical properties of semiconductors with magnetism by adding magnetic atoms to materials or stacking thin layers. This “layering” approach kept the processes separate. Van der Waals magnetic semiconductors change this by allowing excitons and magnetic moments to emerge from the same electronic orbitals.

Pratap Chandra Adak, a postdoctoral researcher in the Laboratory for Nano and Micro Photonics (LaNMP) and lead author of the review, states that in these materials, light and magnetism no longer operate as separate channels. He notes that an exciton isn’t just a passive excitation but can sense spin order and magnons—magnetic waves—and may even control the magnetic state itself.

Key Material Platforms Under Study

The CCNY research team, led by physicist Vinod M. Menon, identifies several specific materials that demonstrate these unique interactions:

• Chromium triiodide
• Nickel phosphorus trisulfide
• Chromium sulfur bromide

According to the Nature Materials review, these platforms allow scientists to identify magnetic states by observing changes in the polarization of light, a process where excitons significantly strengthen magneto-optical effects.

Future Trends in Quantum Memory and Data Readout

The ability to manipulate electron spin and light simultaneously opens a path toward “magneto-photonic” technology. According to the LaNMP researchers, this could lead to the development of all-optical logic and adjustable light-emitting devices.

One of the most significant potential applications is the creation of quantum transducers. These devices would convert signals between microwave and optical frequencies. This capability is essential for connecting different components within future quantum networks, acting as a bridge between different types of quantum information carriers.

The researchers also point toward the possibility of magneto-optic lasers and polaritonic technologies, which would rely on the precise control of light and magnetism at extremely small scales.

Remaining Hurdles in Quantum Material Science

Despite the progress, the field is still largely unexplored. The researchers note a critical need for better theoretical models. Current science lacks the frameworks to predict how excitons, electron spins, lattice vibrations, and photons behave when they all interact at once.

Future research directions identified by the team include:

• Investigating moiré magnetic excitons.
• Developing optical control of spin textures.
• Exploring magnetic exciton polariton condensation.

The collaboration involved a global network of experts, including Florian Dirnberger from the Technical University of Munich, Swagata Acharya of the National Laboratory of the Rockies, Akashdeep Kamra of Rheinland-Pfälzische Technische Universität Kaiserslautern-Landau, and Xiaodong Xu of the University of Washington.

Quantum Magnetism FAQ

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