In a study reported on Aug. 7, 2026, in Nature Physics, MIT physicists described observing how two charge density wave phases emerge and coexist in the rare-earth material erbium tritelluride. The team, led by MIT physics professor Nuh Gedik, cooled atomically thin samples to about -230 degrees Celsius, then used pairs of laser pulses to disrupt the phases and track their recovery.

The dominant phase returned gradually and uniformly regardless of disturbance intensity—a textbook second-order transition. The second, perpendicular phase reformed in isolated pockets that spread, resembling water crystallizing into ice, which the team characterized as a first-order transition.

The first wave has previously been reported to form near -8 degrees Celsius and the second near -113 degrees Celsius. The researchers said the approach could help explain coexistence of phases in more complex materials, including high-temperature superconductors, and was supported by the U.S. Department of Energy, the National Science Foundation and the Gordon and Betty Moore Foundation's EPiQS Initiative.