SciTechDaily – Nanoscience

This Crystal Doesn’t Melt Like Ice: Physicists Capture a Strange New Phase

Physicists at the University of Vienna directly observed the elusive hexatic phase in an atomically thin silver iodide crystal, confirming that covalent two‑dimensional materials can melt via an intermediate state. By sandwiching the crystal between graphene layers and heating it in a scanning transmission electron microscope, the team captured real‑time atomic‑scale melting. Neural‑network analysis identified a narrow temperature window where the hexatic phase appears before the crystal liquefies. The findings contradict classic theories that predict continuous transitions on both sides of the hexatic state.