Researchers at Brown University and the University of Michigan have stabilized a previously elusive crystal phase of matter using engineered silver nanoparticles, reporting unexpected quantum optical behavior at room temperature in a paper published in Science on May 30, 2026.
A Missing Step Between FCC And BCC
Many metals naturally pack atoms into either face-centered cubic (FCC) or body-centered cubic (BCC) arrangements, and they sometimes switch between the two when heated. Theory predicts a series of fleeting transitional arrangements along the so-called Nishiyama–Wassermann pathway, but those intermediate phases are so unstable they have rarely been observed.
The new work captures and locks in one of those intermediate states. “Our work is a little bit like kids playing with LEGO blocks,” said Brown chemistry professor Ou Chen, who led the experimental team. The researchers used 14-faced silver “mecons” — truncated octahedra that fall between a sphere and a cube — coated with flexible molecular chains so they would self-assemble into ordered superlattices matching the predicted transitional structures.
Quantum Optical Surprise
When illuminated, the new superlattices showed signs of deep-strong light-matter coupling, in which electrons inside the silver nanoparticles oscillate in lockstep with light waves and become quantum-mechanically entangled. Such effects are usually only observable at cryogenic temperatures, but here they appear at room temperature, opening a possible route to more practical quantum sensors, modulators and compute components.
Why It Matters
Beyond the materials science result, the work demonstrates a broader strategy: design nanoparticles with specific shapes, then use them as programmable building blocks for entirely new structures. Tim Moore of Sharon Glotzer’s group at Michigan, which performed the supporting simulations, called the result “a fundamental breakthrough in materials science.”
Applications In Sight
Practical devices are still years away, but the team sees promise in low-energy compute and quantum information technologies. “Anytime you’re able to identify a new phase of matter, new applications are going to emerge,” Chen said. The work was supported by multiple NSF and Department of Energy grants.
Reporting based on coverage from Brown University, the University of Michigan and ScienceDaily.