Magnets come in many shapes and sizes, from the simple souvenirs hanging on your refrigerator to the powerful versions used in research labs. What are known as spin waves are caused by the direction one magnon spins. Information can be transmitted via spin waves more efficiently than with electricity, and magnons can be used to glue quantum bits together into powerful computers.
bulky pieces of lab equipment make it difficult to detect magnons. The setup is fine for conducting experiments but not for developing devices. The right material can be peeled into atom-thin, 2D layers, which can be used to see magnons.
In a new article in Nature, the University of Washington, New York University, and Oak Ridge National Laboratory have shown that magnons can pair up with an exciton, which emits light.
The excitons were visible to the naked eye as they perturbed the magnons. For the first time, we can see magnons with an optical effect.
The results may be seen as quantum transduction, in which one quanta of energy is converted to another. The energy of excitons is four orders of magnitude larger than that of magnons, which makes it easy to observe small changes in the magnons. One day, researchers will be able to build quantum information networks that can take information from spin-based quantum bits and convert it to light, a form of energy that can transfer information up to hundreds of miles.
The coherence time was longer than the five-second limit of the experiment. Even though the devices were made of two atom-thin layers, the phenomenon could travel over seven micrometers. One day, these devices could be more efficient. No particles are moving in a spin wave like electrons in an electrical current.
From here, the researchers plan to look at other material candidates. "We are exploring the quantum properties of several 2D materials that you can stack like papers to create all kinds of new physical phenomena."
If magnon- excitoncoupling can be found in other types of magnetic semiconductors, they might emit light in a wider range of colors.
New devices with different properties are being constructed.
More information: Youn Jue Bae et al, Exciton-coupled coherent magnons in a 2D semiconductor, Nature (2022). DOI: 10.1038/s41586-022-05024-1 Journal information: Nature
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