Events

From Bose–Einstein Condensation to Supersolidity: A New Room-Temperature Playground in Halide Perovskites

Wei Bao, Assistant Professor, Department of Materials Science & Engineering at Rensselaer Polytechnic Institute

Presented in person in Goergen 101 and on Zoom

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Abstract

Strong light–matter coupling in optical cavities gives rise to exciton-polaritons, hybrid quasiparticles that provide a powerful platform for exploring collective quantum phenomena such as Bose–Einstein condensation, superfluidity, and supersolidity. Traditionally, most polariton experiments have relied on epitaxially grown semiconductor microcavities operating at cryogenic temperatures, which has limited their accessibility and scalability.

In recent years, lead halide perovskites have emerged as a promising alternative platform for polaritonics at room temperature, owing to their large exciton binding energy, high photoluminescence quantum yield, tunable bandgap, and strong nonlinear interactions. These properties make halide perovskites particularly attractive for realizing robust polaritonic states and nonlinear many-body phenomena under ambient conditions.

In this talk, I will first review recent progress in room-temperature polaritonics based on emerging excitonic materials. I will then present our efforts to grow large, high-quality halide perovskite single crystals and integrate them into optical cavities and nanophotonic structures. Using these platforms, we have observed a series of collective polaritonic phenomena at room temperature, including Bose–Einstein condensation, superfluid behavior, and, most recently, a supersolid phase featuring the coexistence of long-range spatial order and global phase coherence. These results establish halide perovskites as a new room-temperature playground for nonequilibrium quantum many-body physics and open exciting opportunities for polaritonic devices and quantum photonic technologies.

Biography

Wei Bao is an assistant professor in the Department of Materials Science and Engineering at Rensselaer Polytechnic Institute, where his research focuses on optical physics and nanophotonics. Prior to joining RPI, he served as an assistant professor at the University of Nebraska–Lincoln and was a postdoctoral researcher at the University of California, Berkeley. He received his BS in physics, with a minor in chemistry, from Peking University, and his PhD in materials science and engineering from the University of California, Berkeley. His honors include the U.S. Army Research Office Early Career Program Award in 2024, the U.S. National Science Foundation CAREER Award in 2022, and the Light: Science & Applications Rising Star of Light Award in 2022.