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.
Macroscopic quantum effects such as superconductivity, superfluidity, and Bose-Einstein condensation emerge due to the collective coherence of quantum particles. For electronic phase transitions in solids, thermal processes such as random electron-phonon scattering cause dephasing and limit these phenomena to low temperatures. We recently observed superfluorescence in lead halide perovskite thin films at unprecedentedly high temperatures. In superfluorescence, optically excited dipoles synchronize and reach a collectively coherent quantum state. The resulting giant dipole emits a burst of photons. Similar to other macroscopic quantum effects, superfluorescence also requires robust coherence. Hence, the observation of this collective quantum optical effect at high temperatures provides an unprecedented opportunity for the investigation of mechanisms that enable high-temperature collective quantum states in solids. In this presentation, I will discuss our analysis of system-bath interactions that stabilize macroscopic coherence in superfluorescence in perovskites. Our work provides important insights into the design and development of quantum materials for practical applications
Superfluorescence is a quantum optical phenomenon in which an initially excited ensemble of incoherent dipoles first acquire macroscopic coherence and then collectively recombine and radiate a burst of photons. This process is a symmetry breaking macroscopic quantum phase transition similar to superconductivity and Bose-Einstein condensation. Since quantum coherence is extremely fragile at high temperatures, similar to other macroscopic quantum phase transitions, superfluorescence has been almost always observed at cryogenic temperatures. In this presentation I will first present our results on room temperature superfluorescence in lead-halide perovskites and then present the mechanism that enables this exotic quantum phase transition at room temperature.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.