Superradiant phase transition in hybrid perovskites: critical temperature and density

Macroscopic quantum phase transitions in solid-state systems hold promise for advancing high-temperature quantum technologies. However, the practical implementation of such technologies is hindered by rapid thermal dephasing, confining macroscopic quantum phenomena to cryogenic conditions. This limitation emphasizes the need for understanding the mechanisms governing phase transitions, including the properties of materials determining critical temperature and the process leading to macroscopic coherence. In this study, we delve into the superradiant phase transition in perovskites, focusing on critical temperatures and densities influencing the emergence of macroscopically coherent quantum states within electronic excitations in crystalline matter. Our analysis of the phase diagram of PEA:CsPb(Br/Cl) from 78K to 285K reveals a distinctive dome-shaped pattern, akin to quantum phenomena such as superconductivity or superfluidity. This intriguing similarity holds the potential to provide insights into the unknown mechanisms of high-temperature quantum phenomena, potentially paving the way for practical advancements in quantum technologies designed to operate at elevated temperatures.