High-temperature superfluorescence in perovskites*

Creation, and manipulation of macroscopic quantum phases of matter has a significant potential for emerging quantum technologies. However, since quantum phase is extremely fragile under thermal noise, observation of these states has been limited to cryogenic conditions. Here we present that archetypal hybrid perovskite methyl ammonium lead iodide exhibits such a quantum state at high temperatures. Optically excited dipoles first form an incoherent ensemble, then undergo a synchronization process to form a giant dipole. The resulting state collectively emits a burst of radiation in a time scale 3 orders of magnitude faster compared to the lifetime of individual dipoles. This process is called superfluorescence and it is a second order quantum phase transition similar to Bose-Einstein condensation and superconductivity. Observation and study of superfluorescence in these materials provides insight into mechanisms that leads to collective quantum phenomena and development of quantum technologies.