CCNY researchers link light and magnetism in atomically thin materials

CCNY researchers link light and magnetism in atomically thin materials

Physicists at the City College of New York are developing a framework for quantum science centered on materials only a few atoms thick, where magnetism, electric charge, and light operate as interconnected systems rather than independent forces. The research, led by professor of physics Vinod M. Menon at the Laboratory for Nano and Micro Photonics (LaNMP), suggests these interactions could lead to the creation of advanced quantum technologies and optoelectronic devices.

In a review published in Nature Materials titled Excitons in van der Waals magnetic materials, the team examines layered magnetic semiconductors. These materials facilitate interactions between magnetic order and light-generated excitations known as excitons. An exciton is an electrically neutral particle formed when light energizes an electron, causing it to move and leave behind a positively charged hole. These excitons interact with magnons, which are collective waves moving through a material's organized magnetic structure.

Previous attempts to combine magnetism with the optical properties of semiconductors involved stacking thin semiconductors on magnetic materials or adding magnetic atoms to the semiconductors. However, van der Waals magnetic semiconductors allow excitons and magnetic moments to emerge from the same electronic orbitals. This shared origin enables light and magnetism to influence each other internally.

"In these materials, light and magnetism no longer operate as separate channels,"

Pratap Chandra Adak, postdoctoral researcher and lead author, via ScienceDaily

Adak noted that an exciton is not a passive excitation but can sense magnons and spin order, potentially helping to control the magnetic state under specific conditions. The researchers identified several material platforms for these interactions, including chromium sulfur bromide, nickel phosphorus trisulfide, and chromium triiodide.

The review details how these interactions manifest in practical ways:

• Excitons can strengthen magneto-optical effects, allowing the identification of magnetic states through changes in light polarization.
• Magnetic order can influence where excitons are confined and alter their energy.
• Interactions between magnons and excitons can link optical signals with magnetic activity at gigahertz frequencies.
• Exciton polaritons—hybrid particles of light and matter—can transport optical information through the material.

Menon stated that the field has transitioned from simply detecting magnetism in atomically thin crystals to exploring how magnetic order controls light-matter interactions. The goal is to create a coherent framework to guide future developments. Potential applications include all-optical logic, magneto-optic lasers, adjustable light-emitting devices, polaritonic technologies, and magneto-photonic memory and data readout.

The researchers also highlighted quantum transducers, which convert signals between optical and microwave frequencies, as a critical component for connecting future quantum networks. But significant gaps remain. The team noted that many materials are still unexplored and the field lacks theoretical models capable of predicting the simultaneous behavior of photons, electron spins, lattice vibrations, and excitons.

Looking ahead, the researchers plan to investigate the optical control of spin textures, magnetic exciton polariton condensation, moiré magnetic excitons, and the use of microwave-to-optical signal conversion for quantum communication. The CCNY work received support from the Gordon and Betty Moore Foundation and DARPA.

The broader field of 2D materials continues to see diverse breakthroughs. MIT physicists led by Pablo Jarillo-Herrero recently reported in Nature Physics the discovery of orbital magnetism in a helical structure made of three twisted graphene layers. This magnetism persisted to -263 degrees Celsius, the highest reported in carbon-based materials. Similarly, researchers at ETH Zurich and the University of Basel reported in Nature on January 28, 2026, that they used a laser pulse to permanently flip the magnetic polarity of a ferromagnet made of twisted molybdenum ditelluride without using heat.

While these laboratory advances in quantum materials and "twistronics" suggest a future of terahertz-class switching and adaptable topological circuits, industry experts note that silicon remains the dominant material for consumer electronics. The transition from laboratory research to fabrication is expected to take years or decades due to manufacturing complexity and the need for room-temperature stability.