Catenaa, Saturday, February 07, 2026-Researchers have observed a surprising quantum phase in bilayer graphene, where a superfluid appears to freeze into a solid-like state, offering insight into previously elusive supersolids.
The team, led by Cory Dean at Columbia University and Jia Li at the University of Texas at Austin, used two-atom-thick layers of graphene to host excitons, quasiparticles formed from bound electron-hole pairs. In a strong magnetic field, these excitons normally form a frictionless superfluid.
When cooled or thinned in density, however, the superfluid unexpectedly stopped moving, entering an insulating phase that resembles a crystal. Heating the system restored superfluidity, suggesting a reversed phase transition.
Supersolids are a long-theorized state that combine crystalline order with frictionless flow.
Past experiments relied on externally imposed periodic structures, but this graphene system generates the behavior naturally within a crystal lattice.
The results mark the first observation of a superfluid transitioning into a solid-like state without external confinement.
Researchers caution that further measurements are needed to confirm the supersolid nature of the phase.
The work also opens opportunities to explore other 2D materials, potentially stabilizing superfluids and supersolids at higher temperatures and without strong magnetic fields.
Bilayer graphene’s excitons are thousands of times lighter than helium atoms, allowing the formation of quantum states at relatively accessible conditions.
This discovery could advance understanding of exotic quantum matter and guide the development of next-generation quantum devices.
