Exciton-Polaritons with Halide Perovskites

Recently, semiconducting lead halide perovskites with a composition of ABX₃ (where A is commonly CH₃NH₃⁺ (MA⁺) or Cs+; B is Pb²⁺; X is Cl⁻, and Br⁻) have emerged as contenders to GaAs for polaritonic but at room temperature, due to their large exciton binding energy, high photoluminescence (PL) quantum yield, tunable bandgap and high room-temperature nonlinear interaction strength. With chemical vapor deposition (CVD), single-crystalline inorganic halide perovskites have shown polariton condensation. However, due to the limitations of the current growth methods and the fragile nature of perovskites, only small single crystals can be integrated into the optical cavities. Critically, the small sizes prohibit the studies of large-scale phenomena, such as superfluidity formation, XY spin Hamiltonian, and topological effects, due to the limited lattice size and the restricted propagation lengths.

In this talk, I will first introduce our approach [1] to overcome the above size limitation and obtain various types of large halide perovskite single crystals inside optical nanocavities. Due to the uniform confined environment, the solution growth approach shows uniformity, comparable to the MBE-grown GaAs quantum well, enabling submillimeter-large single crystals with superb excitonic quality. These crystals with strongly interacting Wannier-Mott excitons allowed us to successfully demonstrate a polaritonic XY spin Hamiltonian at room temperature. Further, we show that a lattice with many coherently coupled condensates up to 10 x 10 can be achieved. This is a critical step towards the ultimate goal of realizing a room-temperature polaritonic platform on par with MBE-grown GaAs at low temperatures. In addition, we show that the dispersion of the perovskite system has unique advantages for future studies on synthetic non-Abelian gauge fields and topological physics.

Lastly, I will introduce our recent two works using halide perovskite on topological valley Hall polariton condensation [2] and polariton superfluidity [3].

References

[1] Renjie Tao†, Kai Peng†, Louis Haeberlé , Quanwei Li , Dafei Jin , Graham R. Fleming , Stéphane Kéna-Cohen , Xiang Zhang*, Wei Bao*. "Halide perovskites enable polaritonic XY spin Hamiltonian at room temperature" Nature Materials, 21, 761–766 (2022)
[2]. Kai Peng†, Wei Li†, Meng Sun†, Jose Rivero, Chaoyang Ti, Xu Han, Li Ge, Lan Yang, Xiang Zhang*, and Wei Bao* "Topological valley Hall polariton condensation" Nature Nanotechnology. 19, 1283–1289 (2024)
[3]. Kai Peng†, Renjie Tao†, Louis Haeberlé, Quanwei Li, Dafei Jin, Graham R. Fleming, Stéphane Kéna-Cohen, Xiang Zhang*, Wei Bao*. "Room-temperature polariton quantum fluids in halide perovskites" Nature Communications, 13, 7388 (2022)