Normally, the motion of electrons and other subatomic particles are too fast to image, even with the world’s fastest camera. Gedik and his colleagues wondered if they might detect the hybrid particle, and tease out the two particles making up the whole, by catching their signature motions with a super-fast laser. Another group found signs of a hybrid particle, but its exact constituents and its relationship with this exotic excitation were also not clear. In probing NiPS3, that group discovered that an exotic excitation became visible when the material is cooled below its antiferromagnetic transition, though the exact nature of the interactions responsible for this was unclear. Researchers Separate Properties of a Particle from the Particle Itself.Photonic Particle Acceleration with Dielectric Laser Acceleration.: Galaxy Shredded By Milky Way Reconstructed By Volunteer Computer.In contrast, a ferromagnetic material is made up of atoms with spins aligned in the same direction. The microstructure of an antiferromagnet resembles a honeycomb lattice of atoms whose spins are opposite to that of their neighbor. In 2018, a research group in Korea discovered some unexpected interactions in synthesized sheets of NiPS3, a two-dimensional material that becomes an antiferromagnet at very low temperatures of around 150 kelvins, or -123 degrees Celsius. Physicists look for these interactions by condensing chemicals onto surfaces to synthesize sheets of two-dimensional materials, which could be made as thin as one atomic layer. Such interactions, between a material’s atoms, electrons, and other subatomic particles, can lead to surprising outcomes, such as superconductivity and other exotic phenomena. The field of modern condensed matter physics is focused, in part, on the search for interactions in matter at the nanoscale. His co-authors include Emre Ergeçen, Batyr Ilyas, Dan Mao, Hoi Chun Po, Mehmet Burak Yilmaz, and Senthil Todadri at MIT, along with Junghyun Kim and Je-Geun Park of Seoul National University in Korea. Gedik and his colleagues have published their results today in the journal Nature Communications. “Then you could make devices very different from how they work today.” “Imagine if we could stimulate an electron, and have magnetism respond,” says Nuh Gedik, professor of physics at MIT. If these properties could be manipulated, for instance through the newly detected hybrid particles, scientists believe the material could one day be useful as a new kind of magnetic semiconductor, which could be made into smaller, faster, and more energy-efficient electronics. The results are especially relevant, as the team identified the hybrid particle in nickel phosphorus trisulfide (NiPS3), a two-dimensional material that has attracted recent interest for its magnetic properties. Such dual control could enable scientists to apply voltage or light to a material to tune not just its electrical properties but also its magnetism. In principle, an electronic excitation, such as voltage or light, applied to the hybrid particle could stimulate the electron as it normally would, and also affect the phonon, which influences a material’s structural or magnetic properties.
The particle’s exceptional bond suggests that its electron and phonon might be tuned in tandem for instance, any change to the electron should affect the phonon, and vice versa. When they measured the force between the electron and phonon, they found that the glue, or bond, was 10 times stronger than any other electron-phonon hybrid known to date. They determined that the hybrid particle is a mashup of an electron and a phonon (a quasiparticle that is produced from a material’s vibrating atoms). Now MIT physicists have detected another kind of hybrid particle in an unusual, two-dimensional magnetic material. Such paired electrons, or Cooper pairs, are a kind of hybrid particle - a composite of two particles that behaves as one, with properties that are greater than the sum of its parts. When two electrons are bound together, they can glide through a material without friction, giving the material special superconducting properties. In the particle world, sometimes two is better than one.
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