Quantum breakthrough links light and magnetism in atomically thin materials

A newly published scientific review lays out significant strides in an emerging class of ultra-thin materials where beams of light and magnetic behavior become intertwined in ways researchers say were previously out of reach. At the heart of the findings is a phenomenon in which particles created by light, known as excitons, can directly influence a material's magnetic properties, opening a potential path toward switching magnetic states on and off using nothing but light.

The analysis comes from a team at the City College of New York, which has been tracking a rapidly expanding branch of quantum science focused on materials that measure only a handful of atoms in thickness. What sets these materials apart, according to the researchers, is that light, electrical charge and magnetism no longer act as separate, isolated forces within them — instead, the three become tightly coupled, each capable of shaping the others.

The review was produced by physicist Vinod M. Menon and colleagues at his Laboratory for Nano and Micro Photonics, known as LaNMP. The group argues that this tangled relationship between light, charge and the spin of electrons could eventually be harnessed to build a new generation of optoelectronic components and quantum-based technologies, potentially offering engineers a single physical channel through which multiple properties of a material can be controlled at once.

Published in the journal Nature Materials under the title "Excitons in van der Waals magnetic materials," the paper surveys recent advances involving thin, layered semiconductors that carry their own built-in magnetism. In these layered structures, the excitons generated when light strikes the material do not remain isolated; instead they can couple with the material's magnetic ordering and with magnons, the collective ripples of spin that travel through a magnetic lattice much like waves.

The implications extend well beyond a laboratory curiosity. Conventional data storage and computing largely rely on electrical currents to set or read magnetic states, a process that generates heat and consumes substantial energy at scale. If magnetism can instead be nudged using photons, the review suggests, it could pave the way toward memory and logic devices that run faster and with far less energy loss, alongside photonic systems capable of processing information optically rather than electronically.

Such possibilities also feed into the broader push toward quantum technologies, where the ability to manipulate spin, charge and light in a coordinated fashion is considered a building block for future quantum sensors and information-processing hardware. Layered magnetic semiconductors are attractive candidates in this pursuit because their atomic thinness makes it easier to stack, twist or combine them with other two-dimensional materials to engineer bespoke properties.

Even so, the paper is a synthesis of the field's progress rather than an announcement of a working device, and researchers caution that translating these laboratory-scale interactions into practical technology remains a distant goal. Open questions highlighted by the broader research community include whether such light-magnetism coupling can be sustained at room temperature, how stable these ultra-thin magnetic layers are outside controlled conditions, and how the effects might be scaled up for manufacturing.

Researchers in the field are expected to continue probing which combinations of layered materials produce the strongest exciton-magnon interactions and whether the coupling can be tuned electrically or through strain, steps that would need to precede any commercial application. For now, the review is intended to consolidate what has been learned so far and point toward the experiments most likely to move the science from fundamental physics toward usable technology.

Source: ScienceDaily