Researchers at Brown University and the University of Michigan, with senior scientist Yasutaka Nagaoka, synthesized silver nanoparticles shaped like truncated octahedra (nicknamed "mecons") and coated them with sticky molecules so they self-assemble like nanoscale LEGO bricks. Writing in Science, the team stabilized an intermediate crystal phase sitting between the two most common metallic arrangements, face-centered cubic (FCC) and body-centered cubic (BCC), a transitional state predicted by the Nishiyama-Wassermann pathway but never before captured in a real material.
The resulting superlattice displays "deep-strong light-matter coupling" at room temperature: electrons in the silver particles vibrate in unison with light waves and become quantum-mechanically entangled. That behavior normally appears only near absolute zero, so seeing it at room temperature is what makes the result notable.
"Anytime you're able to identify a new phase of matter, new applications are going to emerge," said Brown chemist Ou Chen. The exotic optical properties could feed future quantum computing and quantum sensing systems.